Be still more careful with this mm2 field.

This should fix the bug introduced in #295 that @vhalli and @inheritedburrp hit in #299.

fedmsg_meta_fedora_infrastructure/mm2.py

@@ -74,7 +74,7 @@ def objects(self, msg, **config):
         if 'mirrormanager.crawler' in msg['topic']:
             if 'hosts' in msg['msg']:
                 return set([
-                    'mirrors/%s' % host['host']
+                    'mirrors/%s' % host.get('host', host.get('name'))
                     for host in msg['msg']['hosts']
                 ])
             else: