contrail raises wrong quota exception

This patch reraise OverQuota exception which
come from contrail.

In kilo and Liberty, OverQuota exception is defined
in neutron/common/exceptions.py.In Mitaka, it moved
to neutron_lib project neutron_lib/exceptions.py#L212

Change-Id: I1d3615f073fd3352b74a522604601c02f34bd814
Closes-Bug: #1590930

neutron_plugin_contrail/plugins/opencontrail/contrail_plugin_base.py

@@ -40,6 +40,10 @@
 except ImportError:
     from oslo_log import log as logging
 
+try:
+    from neutron_lib import exceptions as libexc
+except ImportError:
+    libexc = None
 
 # Constant for max length of network interface names
 # eg 'bridge' in the Network class or 'devname' in
@@ -100,6 +104,8 @@ def _raise_contrail_error(info, obj_name):
                 raise getattr(securitygroup, exc_name)(**info)
             if hasattr(allowedaddresspairs, exc_name):
                 raise getattr(allowedaddresspairs, exc_name)(**info)
+            if libexc and hasattr(libexc, exc_name):
+                raise getattr(libexc, exc_name)(**info)
         raise exc.NeutronException(**info)