GRE tunnel key should use fib_index instead of fib_id (VPP-1118)
GRE tunnel key should use fib_index instead of fib_id (VPP-1118)

Follow up fix - vl_api_gre_add_del_tunnel_t_handler should pass
outer_fib_id from API message to vnet_gre_add_del_tunnel() and
not convert it to fib_index, since vnet_gre_add_del_tunnel()
already perform the lookup to get fib_index from fib_id.

Change-Id: I24967a97f82ce018ddef596e556bd3eb1706cb63
Signed-off-by: John Lo <e676165d137051a9de0d8979abbff6c5d0ccb4f0@cisco.com>

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