OFA agent: use hexadecimal IP address in tunnel port name

The remote IP address is used to form the tunnel port name
With some OVS/Linux combinations there is a 15 character limit
on port names, so a name like 'gre-192.168.10.10' does not work.
This fix uses the shorter hexadecimal representation of
the IP address instead.
This problem was reported and fixed for OVS agent.

Closes-Bug: 1294474

Conflicts:
	neutron/plugins/ofagent/agent/ofa_neutron_agent.py

Change-Id: Ieab1eb8a5c430f69aff61a317cc28f23ba95ad2d
(cherry picked from commit c506ebf317e64766369c0bfa97b6af182656ac4c)
Merge "OFA agent: use hexadecimal IP address in tunnel port name" into stable/icehouse