BFD: drop rpc call if packet doesn't match session
BFD: drop rpc call if packet doesn't match session

In a very unlikely scenario, during which a session is removed
and replaced with a different session sharing the same session
index, while a packet is in-flight during RPC call, drop that packet.

Change-Id: If1c4a77fc2ab460bae2435db066a133185b98747
Signed-off-by: Klement Sekera <b8003f27414ca85c37624503b7b4e8f8c829bb4d@cisco.com>

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