L3 agent fetches the external network id once

Rather than fetching the id of the external network each time that
_process_routers is called, get it once and remember it.  If the agent
is ever requested to connect to a different ext-net then it will fetch
the current ext-net to double check for the unlikely event that the
ext-net has changed.  If it has then it will remember the new ext-net.

This is only applicable in the case where there is only one ext-net
that has not been configured explicitly in the config file.  That was
the only case that would cause an RPC message in the first place.

Change-Id: I40bbbf6233131ea5d40122ef9495fd3cb7dc823a
Closes-Bug: #1269567
NSX: make sync backend run more often

This patch bumps the state_sync_interval from 120 seconds to 10 seconds
so that resource's operation status are synced to the db quicker. This cuts
the amount of time that tempest takes to run by half.

Closes-bug: 1285338
Co-Authored-By: Salvatore Orlando <salv.orlando@gmail.com>
Change-Id: I494a6f95c2321befc3c0bfedc719e18a1826d9d5
Remove unused method update_fixed_ip_lease_expiration

This should have been log removed here:
	Ifcb4f093c92904ceb896438987d53e692eb7fb26

Change-Id: I9395fea531365b82a0cd16f29d6392199e2d9c22
Closes-bug: #1287407
Implementaion of Mechanism driver for
Brocade VDX cluster of switches

Change-Id: Ic1649f7cee73a41f286e12d8ba6ca30be6261cfe
Implements: blueprint brocade-ml2-mechanism-driver
Fix race condition in update_floatingip_statuses

If a floatingip is deleted before update_floatingip_statuses() is processed
FloatingIPNotFound is raised.

Change-Id: Idf03fda75ccd147673169c24e79921ca6d8fe754
Closes-bug: #1288036
Do fip_status migration only for l3-capable plugins

The migration was initially performed for all plugins, causing
failures for plugins for which the initial L3 migration was
not performed.

Change-Id: I4a48a13202a4125f032a3e80aa567f7979d2c335
Closes-Bug: 1287630
Merge "NSX: make sync backend run more often"
Merge "L3 agent fetches the external network id once"
Merge "Fix race condition in update_floatingip_statuses"
Merge "Implementaion of Mechanism driver for Brocade VDX cluster of switches"
Merge "Do fip_status migration only for l3-capable plugins"
Merge "Remove unused method update_fixed_ip_lease_expiration"