of1.3: Add special group identifier values defined on OpenFlow 1.3.1

This patch add missing group special values of OpenFlow 1.3, added to
the 1.3.1 version.

It is useful to create a flow_mod message with an out_group with no >
group restrictions and for flow_stats messages.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>