Remove devnull from post regex

This reverts commit 8882b4fd989e0601c8a5706db471a9fa673b6931.

This was a temporary measure, from a long time ago, which is no
longer needed.

Change-Id: Ia5a3fb5db9b7cd471585fb6ff6e286e600d694a2

modules/openstack_project/files/zuul/layout-dev.yaml

@@ -52,7 +52,7 @@ pipelines:
     trigger:
       gerrit:
         - event: ref-updated
-          ref: ^(?!(devnull|refs/.*)).*$
+          ref: ^(?!refs/).*$
 
   - name: tag
     description: This pipeline runs jobs in response to any tag event.

modules/openstack_project/files/zuul/layout.yaml

@@ -89,7 +89,7 @@ pipelines:
     trigger:
       gerrit:
         - event: ref-updated
-          ref: ^(?!(devnull|refs/.*)).*$
+          ref: ^(?!refs/).*$
 
   - name: tag
     description: This pipeline runs jobs in response to any tag event.