Include external network bridge for vpn agent

fix to make external network bridge configurable
in the vpn_agent.ini config file. Defaults to
nil.

Change-Id: Iddb6ff6296b8f2d42d97fdcb36a9819a4a995034
Merge "Include external network bridge for vpn agent"
ml2-plugin: update security group option

In Icehouse, security group configuration is enabled from the plugin and
should be enabled by a boolean value instead of a firewall_driver like
before.
If security group is enable, we should ensure firewall_driver is true or
a specific driver.
If security group is disabled, we should use Noop firewall driver.
Patch in Icehouse: http://git.io/Bb-PHQ

Change-Id: I0d0ca2fb80d21a439c5e096dcd978e956e6662fd
Signed-off-by: Emilien Macchi <emilien.macchi@enovance.com>
Add optional dependency mysql -> neutron-server

In cases where neutron server is on the same node
as mysqld it is desirable to have the database
running before the service.

Change-Id: I0a6c3a1d6481b4250a0a948c3e5a14e5a0a5e7de
Merge "ml2-plugin: update security group option"
Merge "Add optional dependency mysql -> neutron-server"