Hold kolla meetings in #openstack-kolla

At the recent kolla virtual PTG we agreed to move IRC meetings to

https://etherpad.openstack.org/p/kolla-train-ptg

Change-Id: I7ddb3c32d8143fb86136b007558e82f78308224d

meetings/kolla-team-meeting.yaml

@@ -4,7 +4,7 @@ agenda_url: https://wiki.openstack.org/wiki/Meetings/Kolla
 schedule:
   - time:       '1500'
     day:        Wednesday
-    irc:        openstack-meeting-4
+    irc:        openstack-kolla
     frequency:  weekly
     start_date: 20180625
 chair: Mark Goddard (mgoddard)