contint: deny Zuul gearman port (4370) beside localhost

Zuul comes with a build in Gearman daemon. At first its only worker will
be the Jenkins master installed on the same box, they will communicates
over the loopback 127.0.0.1.

We can not give access to gearman from labs machine or from the rest of
the Wikimedia cluster to prevent someone from triggering unwanted jobs.
Hence why I firewall out the port.

Change-Id: I708d562a02a98a9e603bd6afbd7399d737cc4322
zuul: dependencies for Gearman based version

The new version of Zuul requires a few more packages: pbr, gear and
apsscheduler. All of them have been uploaded on apt.wikimedia.org over
the last few months.

Change-Id: I38e71600d00516ffe6c8e144c7c36e83b2e008f5
Merge "contint: deny Zuul gearman port (4370) beside localhost" into production
Merge "zuul: dependencies for Gearman based version" into production