bgp_zebra_nht_test: Test case to sync nexthop states
bgp_zebra_nht_test: Test case to sync nexthop states

This patch adds a test case to test if the path, which came after the
NEXTHOP_UPDATE message was received from Zebra, is updated by reflecting
the nexthop cache.

Signed-off-by: IWASE Yusuke <bb80e84cc9f5a8f01385872ee89032beb5d4eba7@gmail.com>

fujita/gobgp,osrg/gobgp,a16/gobgp,j-kato/gobgp,tamihiro/gobgp,fujita/gobgp,j-kato/gobgp,tamihiro/gobgp,a16/gobgp,a16/gobgp,a16/gobgp,a16/gobgp,j-kato/gobgp,fujita/gobgp,a16/gobgp,osrg/gobgp,tamihiro/gobgp,osrg/gobgp,tamihiro/gobgp,osrg/gobgp,a16/gobgp,fujita/gobgp