Ensure that members is a list

self.properties.get('members') should not be None.  Ensure that
an empty list is returned instead.

Change-Id: I01d191eafebac30ad25505b312ff6e936181bdbf
Closes-Bug: #1255697

heat/engine/resources/neutron/loadbalancer.py

@@ -320,6 +320,7 @@ class LoadBalancer(resource.Resource):
                              'running on the members.')},
         'members': {
             'Type': 'List',
+            'Default': [],
             'UpdateAllowed': True,
             'Description': _('The list of Nova server IDs load balanced.')},
     }
@@ -331,9 +332,8 @@ def handle_create(self):
         client = self.neutron()
         nova_client = self.nova()
         protocol_port = self.properties['protocol_port']
-        members = self.properties.get('members') or []
 
-        for member in members:
+        for member in self.properties.get('members'):
             address = nova_utils.server_to_ipaddress(nova_client, member)
             lb_member = client.create_member({
                 'member': {
@@ -370,7 +370,7 @@ def handle_update(self, json_snippet, tmpl_diff, prop_diff):
 
     def handle_delete(self):
         client = self.neutron()
-        for member in self.properties.get('members', []):
+        for member in self.properties.get('members'):
             member_id = db_api.resource_data_get(self, member)
             try:
                 client.delete_member(member_id)