ofproto-dpif: Add test case for OF1.4 packet-in.

The test case current fails and shows a bug when OF1.4 is used between
the controller and the switch, the packet-in message still uses OF1.3
wire protocol version.

Signed-off-by: Shu Shen <shu.shen@radisys.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>