Add missing match in OVS agent tunnel mac leaning

Learned flows introduced in commit a369f9e39691c01a4e4f7f8668cb37fc17ba03b3
to learn remote mac addresses on tunnels currently only match local VLAN,
but not destination mac address, as a consequence, connectivity may be
erratic as soon as more than two agents are used

Change-Id: I467e47d0dd2c1e5aca12a4e240e348116d530d4f
Closes-Bug: #1219074
Merge "Add missing match in OVS agent tunnel mac leaning"