zuul.eqiad.wmnet. IN CNAME gallium.wikimedia.org.

The internal Jenkins slaves are fetching Zuul references from gallium
using: git://integration.wikimedia.org/

That host is really meant for public consumption and might well be moved
out of gallium in favor of a shared Varnish cache.

The new entry zuul.eqiad.wmnet. points to the server currently hosting
Zuul, aka gallium.wikimedia.org.

Once this DNS entry is made available, Jenkins slaves should be made to
use that entry instead of integration.wikimedia.org.

bug: 59774
Change-Id: I7d65a0882f400d8c316754a8802a264c25f186bf