Validate ip6 interface fib tables early on
Validate ip6 interface fib tables early on

This should avoid random crashes due to reception of packets (multicast
in particular) before ip6 addresses are configured on the interfaces.

Change-Id: Ibcf1a5a2ae2fa75f8b57da1b2f09f32c081210d7
Signed-off-by: Florin Coras <c9715e5cdf0718c2e9b10678757dfb027875eba2@cisco.com>

chrisy/vpp,vpp-dev/vpp,vpp-dev/vpp,chrisy/vpp,vpp-dev/vpp,chrisy/vpp,FDio/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,vpp-dev/vpp,chrisy/vpp,vpp-dev/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp