Code Sync from neutron project to newly created neutron-tempest-plugin

* The following commit sync the code from following hash:
  start_hash: 7279aa35851110a4933a10b58b2758a2bc3933a3
  end_hash: 6e911a49a9e630878f4c46f61fde3964be550880

Change-Id: I371aa4d5f043f695df04b98b0f485c8f0548f2b3
diff --git a/neutron_tempest_plugin/config.py b/neutron_tempest_plugin/config.py
index 6830b18..804fece 100644
--- a/neutron_tempest_plugin/config.py
+++ b/neutron_tempest_plugin/config.py
@@ -34,6 +34,10 @@
                 default=False,
                 help='Image that supports features that cirros does not, like'
                      ' Ubuntu or CentOS supporting advanced features'),
+    cfg.StrOpt('agent_availability_zone',
+               help='The availability zone for all agents in the deployment. '
+                    'Configure this only when the single value is used by '
+                    'all agents in the deployment.'),
 ]
 
 # TODO(amuller): Redo configuration options registration as part of the planned