Fix test_clients_monasca failure
Fix test_clients_monasca failure

'cafile','certfile','keyfile' and 'insecure'
 need mock override.

Change-Id: I289904ed38f22d4475fe04f2005b795d07cb8d83
Closes-Bug: #1658553

stackforge/watcher,openstack/watcher,openstack/watcher,stackforge/watcher