Added Nat Config in vpn-service feature pom.
Added Nat Config in vpn-service feature pom.

Change-Id: Id09a72bd02bd4f82f9cdf4c28a291eb3bd52924a
Signed-off-by: Aswin Suryanarayanan <245ded2fd329681a343a9940c2cf4910bae21c4f@redhat.com>

opendaylight/netvirt,opendaylight/netvirt,opendaylight/netvirt,opendaylight/netvirt,opendaylight/netvirt