fix campaign-status to work on single campaign

[zouharvi]

The bugfix is comically simple:

-        r'^campaign-status/(?P<campaign_name>[a-zA-Z0-9]+(,[a-zA-Z0-9]+))*/'
+        r'^campaign-status/(?P<campaign_name>[a-zA-Z0-9]+(,[a-zA-Z0-9]+)*)/'