Add zuul-dev.openstack.org.

And connect it to the firehose.

Change-Id: Id860ff329e33a588d669608e5402bdb3765001dd
Reviewed-on: https://review.openstack.org/28742
Reviewed-by: Khai Do <zaro0508@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Approved: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins