This reverts commit 547d2b590f.
I misunderstood bnemec's statements, apparently those two don't
do releases anymore:
"Both the zmq and pika drivers have been removed from
oslo.messaging so those two repos can actually be retired
once we no longer ci releases that contain the drivers.
In the meantime there isn't any need to branch them since
there isn't any development going on."
Change-Id: I79a945da72dee65bc4d8a6611ed6394d51ac35ae
43847d5877