Allow to configure max vlans for trunk port tests

In NFV baremetal deployments, the number of vlans available for trunk
ports may be constrained. This patch allows to configure
max_networks_per_project to accommodate for those environments.

Change-Id: Ie0f04649313aed41498cf60f7de0eb44cee17b1c
diff --git a/neutron_tempest_plugin/config.py b/neutron_tempest_plugin/config.py
index 804fece..d6db315 100644
--- a/neutron_tempest_plugin/config.py
+++ b/neutron_tempest_plugin/config.py
@@ -38,6 +38,11 @@
                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.'),
+    cfg.IntOpt('max_networks_per_project',
+               default=4,
+               help='Max number of networks per project. '
+                    'Configure this only when project is limited with real '
+                    'vlans in deployment.'),
 ]
 
 # TODO(amuller): Redo configuration options registration as part of the planned