Fix l2 pop doesn't propagate ip address updates

Propagates ip address changes when an ip address is :
added, removed, or changed.
Add a new rpc call for the updates of forwarding informations.

Fixes: Bug #1234137
Change-Id: Ib5b971bd02f20a0ea73f88ce9685e944226bb5a2
change port status only if port is bound to the good host

if host is set in the rpc message update_device_up/down sent by the agent,
the port status will be changed only if the port is bound to the host.

Change-Id: I0e607c734fbebf0b69f83c3bbd3e25a9783672dc
Closes-Bug: #1224967
Arista ML2 mechanism driver clean up and integration with port binding

fixes bug: 1215097

This patch addresses minor cleanups and integration with port binding
and dhcp support into Arista ML2 mechanism driver.

Change-Id: Icebc4aa1c57278171cc6b5209107b8eab833249c
Fix downgrade in migration

In folsom_initial name of table nexusport_bindings to drop was not
correct.

Change-Id: Icb805f3e06c4e05708d11927b24a494c8cc7944f
Merge "change port status only if port is bound to the good host"
Merge "Arista ML2 mechanism driver clean up and integration with port binding"
Merge "Fix l2 pop doesn't propagate ip address updates"
Merge "Fix downgrade in migration"