Fix comment for persistent nodes

Fix comment update missed previously.

Change-Id: Ifdf52944efa4da960c26489b9332e6233937334b

zuul/openstack_functions.py

@@ -53,8 +53,8 @@ def set_node_options(item, job, params):
     wheel_re = r'^wheel-(build|release)-.*$'
     reprepro_re = r'^reprepro-(import|release)-.*$'
     signing_re = r'^tag-releases$'
-    # jobs run on the persistent proposal, release, and wheel build
-    # workers
+    # jobs run on the persistent proposal, release, signing, and wheel
+    # build workers
     if (re.match(proposal_re, job.name) or
         re.match(release_re, job.name) or
         re.match(hook_re, job.name) or