bgpd: free bgp vpn policy

bgpd: free bgp vpn policy

The bgp vpn policy had some attribute not free when the function bgp_free was called leading to memory leak as shown below.

./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251:Direct leak of 592 byte(s) in 2 object(s) allocated from:
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #0 0x7f4b7ae92037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #1 0x7f4b7aa96e38 in qcalloc lib/memory.c:105
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #2 0x7f4b7aa9bec9 in srv6_locator_chunk_alloc lib/srv6.c:135
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #3 0x56396f8e56f8 in ensure_vrf_tovpn_sid_per_af bgpd/bgp_mplsvpn.c:752
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #4 0x56396f8e608a in ensure_vrf_tovpn_sid bgpd/bgp_mplsvpn.c:846
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #5 0x56396f8e075d in vpn_leak_postchange bgpd/bgp_mplsvpn.h:259
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #6 0x56396f8f3e5b in vpn_leak_postchange_all bgpd/bgp_mplsvpn.c:3397
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #7 0x56396fa920ef in bgp_zebra_process_srv6_locator_chunk bgpd/bgp_zebra.c:3238
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #8 0x7f4b7abb2913 in zclient_read lib/zclient.c:4134
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #9 0x7f4b7ab62010 in thread_call lib/thread.c:1991
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #10 0x7f4b7aa5a418 in frr_run lib/libfrr.c:1185
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #11 0x56396f7d756d in main bgpd/bgp_main.c:505
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #12 0x7f4b7a479d09 in __libc_start_main ../csu/libc-start.c:308
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251:Direct leak of 32 byte(s) in 2 object(s) allocated from:
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #0 0x7f4b7ae92037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #1 0x7f4b7aa96e38 in qcalloc lib/memory.c:105
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #2 0x56396f8e31b8 in vpn_leak_zebra_vrf_sid_update_per_af bgpd/bgp_mplsvpn.c:386
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #3 0x56396f8e3ae8 in vpn_leak_zebra_vrf_sid_update bgpd/bgp_mplsvpn.c:448
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #4 0x56396f8e09b0 in vpn_leak_postchange bgpd/bgp_mplsvpn.h:271
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #5 0x56396f8f3e5b in vpn_leak_postchange_all bgpd/bgp_mplsvpn.c:3397
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #6 0x56396fa920ef in bgp_zebra_process_srv6_locator_chunk bgpd/bgp_zebra.c:3238
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #7 0x7f4b7abb2913 in zclient_read lib/zclient.c:4134
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #8 0x7f4b7ab62010 in thread_call lib/thread.c:1991
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #9 0x7f4b7aa5a418 in frr_run lib/libfrr.c:1185
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #10 0x56396f7d756d in main bgpd/bgp_main.c:505
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #11 0x7f4b7a479d09 in __libc_start_main ../csu/libc-start.c:308
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251:Direct leak of 32 byte(s) in 2 object(s) allocated from:
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #0 0x7f4b7ae92037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #1 0x7f4b7aa96e38 in qcalloc lib/memory.c:105
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #2 0x56396f8e5730 in ensure_vrf_tovpn_sid_per_af bgpd/bgp_mplsvpn.c:753
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #3 0x56396f8e608a in ensure_vrf_tovpn_sid bgpd/bgp_mplsvpn.c:846
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #4 0x56396f8e075d in vpn_leak_postchange bgpd/bgp_mplsvpn.h:259
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #5 0x56396f8f3e5b in vpn_leak_postchange_all bgpd/bgp_mplsvpn.c:3397
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #6 0x56396fa920ef in bgp_zebra_process_srv6_locator_chunk bgpd/bgp_zebra.c:3238
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #7 0x7f4b7abb2913 in zclient_read lib/zclient.c:4134
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #8 0x7f4b7ab62010 in thread_call lib/thread.c:1991
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #9 0x7f4b7aa5a418 in frr_run lib/libfrr.c:1185
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #10 0x56396f7d756d in main bgpd/bgp_main.c:505
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-    #11 0x7f4b7a479d09 in __libc_start_main ../csu/libc-start.c:308
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-
./bgp_srv6l3vpn_to_bgp_vrf.test_bgp_srv6l3vpn_to_bgp_vrf/r2.bgpd.asan.603251-SUMMARY: AddressSanitizer: 656 byte(s) leaked in 6 allocation(s).

Signed-off-by: ryndia <dindyalsarvesh@gmail.com>