Modify VTN WebAPI to build using JDK 1.8
Modify VTN WebAPI to build using JDK 1.8

Change-Id: Id701962eea756e2a8e11bebf7d91361d63286c8d
Signed-off-by: gvrangan <d9a771b3744faa7dccd6990d6070efda015ad310@hcl.com>

opendaylight/vtn,opendaylight/vtn,opendaylight/vtn,opendaylight/vtn,opendaylight/vtn,opendaylight/vtn,opendaylight/vtn