Catching 500 from heat during stack-create

-fixing very weird behaviour, that returns 500
 from heat, for a while after a stack-create
 if we call resource-list
-this is some internal heat error trying to access
 not existent nova instance

Fixes-bug: #1301787
Change-Id: I9728affed707cc509b5ea466d87bf8835959e5bf

tuskar_ui/api.py

@@ -459,6 +459,11 @@ class Overcloud(base.APIResourceWrapper):
                                                         self.stack.stack_name)]
         except heatclient.exc.HTTPNotFound:
             resources = []
+        except heatclient.exc.HTTPInternalServerError:
+            # TODO(lsmola) There is a weird bug in heat, that after
+            # stack-create it returns 500 for a little while. This can be
+            # removed once the bug is fixed.
+            resources = []
 
         if not with_joins:
             return [Resource(r, request=self._request) for r in resources]