Use a specific network for the test

If integration tests are executed in an environment with multiple nics,
nova complains and the instance does not start. Given that the
shared_network parameter is already available with that specific
meaning, use it on instance creation.
The default value (None) should ensure that the default behavior
does not change.

Change-Id: I8554ebf111cad829deb34d3d23d18f72d7f13554

trove/tests/scenario/runners/replication_runners.py

@@ -63,6 +63,7 @@ class ReplicationRunner(TestRunner):
             self.instance_info.name + replica_name,
             self.instance_info.dbaas_flavor_href,
             self.instance_info.volume, slave_of=master_id,
+            nics=self.instance_info.nics,
             replica_count=replica_count)
         replica_id = replica.id