Add initial setup for magnum in shade

Start by adding the client, following same structure
as the other ones.

Change-Id: I499f9fdda08743f7b67afcc1c2f9b07df471a041

requirements.txt

@@ -20,5 +20,6 @@ python-ironicclient>=0.10.0
 python-swiftclient>=2.5.0
 python-heatclient>=0.3.0
 python-designateclient>=2.1.0
+python-magnumclient>=2.1.0
 
 dogpile.cache>=0.5.3

shade/openstackcloud.py

@@ -35,6 +35,7 @@ from heatclient.common import template_utils
 from heatclient import exc as heat_exceptions
 import keystoneauth1.exceptions
 import keystoneclient.client
+import magnumclient.client
 import neutronclient.neutron.client
 import novaclient.client
 import novaclient.exceptions as nova_exceptions
@@ -262,6 +263,7 @@ class OpenStackCloud(object):
         self._swift_service_lock = threading.Lock()
         self._trove_client = None
         self._designate_client = None
+        self._magnum_client = None
 
         self._raw_clients = {}
 
@@ -856,6 +858,13 @@ class OpenStackCloud(object):
                 'database', troveclient.client.Client)
         return self._trove_client
 
+    @property
+    def magnum_client(self):
+        if self._magnum_client is None:
+            self._magnum_client = self._get_client(
+                'container', magnumclient.client.Client)
+        return self._magnum_client
+
     @property
     def neutron_client(self):
         if self._neutron_client is None: