Ouroboros.

Don't let datanommer read in a backlog from itself.

roles/fedmsg/base/templates/base.py.j2

@@ -7,6 +7,7 @@ config = dict(
     environment="prod",
     {% endif %}
 
+    {% if not ansible_hostname.startswith('busgateway') %}
     # These options provide a place for hub processes to write out their last
     # processed message.  This let's them read it in at startup and figure out
     # what kind of backlog they have to deal with.
@@ -18,6 +19,7 @@ config = dict(
     {% else %}
     datagrepper_url="https://apps.fedoraproject.org/datagrepper/raw",
     {% endif %}
+    {% endif %}
 
     # This used to be set to 1 for safety, but it turns out it was
     # excessive.  It is the number of seconds that fedmsg should sleep