Update example gerrit messages for new syntax

Change-Id: Id8f1ab1dfbe98411b71f7a7558664c950b93893f
diff --git a/doc/source/zuul.rst b/doc/source/zuul.rst
index 6e9fb05..0d63512 100644
--- a/doc/source/zuul.rst
+++ b/doc/source/zuul.rst
@@ -1046,9 +1046,9 @@
 recheck changes for the gate and check pipelines respectively::
 
   ./tools/zuul-changes.py --review-host=review.openstack.org \
-      http://zuul.openstack.org/ gate 'reverify no bug'
+      http://zuul.openstack.org/ gate 'reverify'
   ./tools/zuul-changes.py --review-host=review.openstack.org \
-      http://zuul.openstack.org/ check 'recheck no bug'
+      http://zuul.openstack.org/ check 'recheck'
 
 If you send a SIGUSR2 to the zuul-server process, Zuul will dump a stack
 trace for each running thread into its debug log. This is useful for