Revert "Make tripleo-buildimage-overcloud-full-centos-7 non-voting"

This reverts commit db2d26a75f331e99f6e39d9e6775fc5f48c0cc90.

The bad upstream RPM has been removed, and the job no longer fails.
The jobs are part of the template, so don't need to be explicitly
listed as they were previously, however.

Related-Change: https://review.openstack.org/619625
Change-Id: I138b7f6bdef1d955a6e0babf228543ab2530159a

.zuul.d/jobs.yaml

@@ -17,8 +17,6 @@
         - dib-functests-bionic-python3-image
         - dib-functests-bionic-python3-extras
         - dib-functests-bionic-python3-containers
-        - tripleo-buildimage-overcloud-full-centos-7:
-            voting: false
         - openstack-tox-lower-constraints
 
     gate:
@@ -26,8 +24,6 @@
         - dib-functests-trusty-python2
         - dib-functests-xenial-python3
         - dib-functests-centos7-python2
-        - tripleo-buildimage-overcloud-full-centos-7:
-            voting: false
         - openstack-tox-lower-constraints
 
 - job: