Never skip jobs when .zuul.yaml is changed

This is a partial revert of https://review.opendev.org/650138/

Currently it is possible to send a review which only touches
.zuul.yaml and changes the functional/tempest/grenade jobs
in a way that breaks them (for example, by removing 'voting: false',
or adding a new job of the said type, or altering their definition
with new parameters). Such changes would not be gated, thus
allowing it to be merged.

Change-Id: Id2b1476fbe0ae7bffd8f64e6f870bdc3721abbb8

.zuul.yaml

@@ -24,7 +24,6 @@
               - ^contrib/block-box.*$
               - ^doc/.*$
               - ^releasenotes/.*$
-              - ^.zuul\.yaml$
         - cinder-rally-task:
             voting: false
         - openstack-tox-pylint:
@@ -49,7 +48,6 @@
               - ^setup.cfg$
               - ^tools/.*$
               - ^tox.ini$
-              - ^.zuul\.yaml$
         - openstack-tox-functional:
             voting: false
             irrelevant-files: *functional-irrelevant-files