Fix the status code of over quota response

Server will response 403 instead of 500 when quota exceeded.

Change-Id: I3cd26929c2a4b1011bea957d59481409e48403de
Closes-Bug: #1799110

zun/api/controllers/v1/containers.py

@@ -470,12 +470,7 @@ class ContainersController(base.Controller):
                 except TypeError as e:
                     raise e
                 check_kwargs[res_name] = total
-            try:
-                QUOTAS.limit_check(context, project_id, **check_kwargs)
-            except exception.OverQuota as exc:
-                # Set HTTP response status code
-                pecan.response.status = 403
-                raise exc
+            QUOTAS.limit_check(context, project_id, **check_kwargs)
 
         _check_deltas(context, deltas)
 

zun/common/exception.py

@@ -707,6 +707,7 @@ class ServerNotUsable(ZunException):
 
 class OverQuota(ZunException):
     message = _("Quota exceeded for resources: %(overs)s")
+    code = 403
 
 
 class QuotaNotFound(NotFound):