zebra: Fix last sent command to protocol

zebra: Fix last sent command to protocol

With the addition of VRF's we were not properly
storing the last sent command to individual
protocols from zebra.  This commit fixes this:

Pre-Fix:
Client: bgp
------------------------
FD: 14
Route Table ID: 0
Connect Time: 00:10:51
Not registered for Nexthop Updates
Last Msg Rx Time: 00:10:51
Last Msg Tx Time: 00:00:04
Last Rcvd Cmd: ZEBRA_REDISTRIBUTE_ADD
Last Sent Cmd: (null)

Post-Fix:
Client: bgp
------------------------
FD: 14
Route Table ID: 0
Connect Time: 00:02:42
Not registered for Nexthop Updates
Last Msg Rx Time: 00:02:42
Last Msg Tx Time: 00:00:09
Last Rcvd Cmd: ZEBRA_REDISTRIBUTE_ADD
Last Sent Cmd: ZEBRA_INTERFACE_UP

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>