nhrpd: cleans up shortcut cache entries on termination

nhrpd: cleans up shortcut cache entries on termination

nhrp_shortcut_terminate() previously was just freeing the associated AFI shortcut
RIBs and not addressing existing shortcut cache entries. This cause a use after
free issue in vrf_terminate() later in the terminate sequence

NHRP: Received signal 7 at 1717516286 (si_addr 0x1955d, PC 0x7098786912c0); aborting...
NHRP: zlog_signal+0xf5                   709878ad1255     7fff3d992eb0 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: core_handler+0xb5                  709878b0db85     7fff3d992ff0 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: __sigaction+0x50                   709878642520     7fff3d993140 /lib/x86_64-linux-gnu/libc.so.6 (mapped at 0x709878600000)
NHRP:     ---- signal ----
NHRP: __lll_lock_wait_private+0x90       7098786912c0     7fff3d9936d8 /lib/x86_64-linux-gnu/libc.so.6 (mapped at 0x709878600000)
NHRP: pthread_mutex_lock+0x112           709878698002     7fff3d9936e0 /lib/x86_64-linux-gnu/libc.so.6 (mapped at 0x709878600000)
NHRP: _event_add_read_write+0x63         709878b1f423     7fff3d993700 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: zclient_send_message+0xd4          709878b37614     7fff3d993770 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: nhrp_route_announce+0x1ad          5ab34d63d39d     7fff3d993790 /usr/lib/frr/nhrpd (mapped at 0x5ab34d621000)
NHRP: nhrp_shortcut_cache_notify+0xd8     5ab34d63e758     7fff3d99d4e0 /usr/lib/frr/nhrpd (mapped at 0x5ab34d621000)
NHRP: nhrp_cache_free+0x165              5ab34d632f25     7fff3d99d510 /usr/lib/frr/nhrpd (mapped at 0x5ab34d621000)
NHRP: hash_iterate+0x4d                  709878ab949d     7fff3d99d540 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: nhrp_cache_interface_del+0x37      5ab34d633eb7     7fff3d99d580 /usr/lib/frr/nhrpd (mapped at 0x5ab34d621000)
NHRP: nhrp_if_delete_hook+0x26           5ab34d6350d6     7fff3d99d5a0 /usr/lib/frr/nhrpd (mapped at 0x5ab34d621000)
NHRP: if_delete_retain+0x3d              709878abcd1d     7fff3d99d5c0 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: if_delete+0x4c                     709878abd87c     7fff3d99d600 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: if_terminate+0x53                  709878abda83     7fff3d99d630 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: vrf_terminate_single+0x24          709878b23c74     7fff3d99d670 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: nhrp_request_stop+0x34             5ab34d636844     7fff3d99d690 /usr/lib/frr/nhrpd (mapped at 0x5ab34d621000)
NHRP: frr_sigevent_process+0x53          709878b0df53     7fff3d99d6a0 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: event_fetch+0x6c5                  709878b20405     7fff3d99d6c0 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: frr_run+0xd3                       709878ac8163     7fff3d99d840 /usr/lib/frr/libfrr.so.0 (mapped at 0x709878a00000)
NHRP: main+0x195                         5ab34d631915     7fff3d99d960 /usr/lib/frr/nhrpd (mapped at 0x5ab34d621000)
NHRP: __libc_init_first+0x90             709878629d90     7fff3d99d980 /lib/x86_64-linux-gnu/libc.so.6 (mapped at 0x709878600000)
NHRP: __libc_start_main+0x80             709878629e40     7fff3d99da20 /lib/x86_64-linux-gnu/libc.so.6 (mapped at 0x709878600000)
NHRP: _start+0x25                        5ab34d631b65     7fff3d99da70 /usr/lib/frr/nhrpd (mapped at 0x5ab34d621000)

Signed-off-by: Dave LeRoy <dleroy@labn.net>