Make Heat and Neutron clients creation lazy (just-in-time).

Change-Id: I14bf6b9271d81049a954946640be4c6dc7a1eb85

tobiko/common/managers/network.py

@@ -18,7 +18,15 @@ class NetworkManager(object):
     """Manages Neutron Resources."""
 
     def __init__(self, client_manager):
-        self.client = client_manager.neutron_client
+        self._client_manager = client_manager
+
+    _client = None
+
+    @property
+    def client(self):
+        if not self._client:
+            self._client = self._client_manager.network_client
+        return self._client
 
     def create_sg_rules(self, rules, sg_id):
         """Creates security group rules."""

tobiko/common/managers/stack.py

@@ -41,10 +41,18 @@ class StackManager(object):
     """Manages Heat stacks."""
 
     def __init__(self, client_manager, templates_dir, wait_interval=5):
-        self.client = client_manager.heat_client
+        self._client_manager = client_manager
         self.templates_dir = templates_dir
         self.wait_interval = wait_interval
 
+    _client = None
+
+    @property
+    def client(self):
+        if not self._client:
+            self._client = self._client_manager.heat_client
+        return self._client
+
     def load_template(self, template_path):
         """Loads template from a given file."""
         _, template = template_utils.get_template_contents(template_path)