l2pop: Allow network types overridable

Currenly "tunnel_types" is used for two different purposes; l2pop and
check_segment_for_agent.  This commit introduces a new agent
configuration "l2pop_network_types" to allow overriding the former.

Will be used by ofagent, which wants l2pop info for TYPE_VLAN.

Change-Id: Ia83a94b6661aa36afa8bfeb073101171ffde62a9
ofagent: bye bye br-tun

WIP

Implements: blueprint ofagent-merge-bridges
Change-Id: I21ee1c6d141863182b487e10c7bfe911b1a472ab
ml2: make get_device_details report mac address as well

Change-Id: Icaa26448a370dd75d09e95ed439df5b486a862cf
ofagent: Try to populate LOCAL_OUT table

Change-Id: Ie807d753ff125682cf0791c685f8767b44dde8fd
ofa_neutron_agent: l2pop_network_types

Change-Id: Id5ed1d40c8a4adbaadf88da4e1d497b358def5bb
cleanup

Change-Id: I5c2c34514389a6aa995562f65b1605b93dd54ee0