Make the use of juju_wait configurable

For compatibility with existing scenario tests the
`configure_gateway_ext_port` helper currently make use of
`juju_wait` when configuring the deployed cloud.

This does not work well if the model you are testing has
applications with non-standard workload status messaging.

Allow to override the behaviour through config step options.

zaza/openstack/utilities/openstack.py

@@ -63,6 +63,9 @@ import tenacity
 import textwrap
 import urllib
 
+import zaza
+import zaza.charm_lifecycle.utils as lifecycle_utils
+
 from zaza import model
 from zaza.openstack.utilities import (
     exceptions,
@@ -794,7 +797,15 @@ def configure_gateway_ext_port(novaclient, neutronclient, net_id=None,
         # NOTE(fnordahl): We are stuck with juju_wait until we figure out how
         # to deal with all the non ['active', 'idle', 'Unit is ready.']
         # workload/agent states and msgs that our mojo specs are exposed to.
-        juju_wait.wait(wait_for_workload=True)
+        if lifecycle_utils.get_config_options().get(
+                'configure_gateway_ext_port_use_juju_wait', True):
+            juju_wait.wait(wait_for_workload=True)
+        else:
+            zaza.model.wait_for_agent_status()
+            test_config = zaza.charm_lifecycle.utils.get_charm_config(
+                fatal=False)
+            zaza.model.wait_for_application_states(
+                states=test_config.get('target_deploy_status', {}))
 
 
 @tenacity.retry(wait=tenacity.wait_exponential(multiplier=1, max=60),