Revert "Use Tempest scenario job to run all scenario tests"

Let's revert the scenario job things till Rocky release and discussion in ML[1].


[1] http://lists.openstack.org/pipermail/openstack-dev/2018-May/130394.html

This reverts commit 5408617a83.

Change-Id: I656aed531fdec9a8eb6c10915d736769a712e7d8

.zuul.yaml

@@ -22,21 +22,6 @@
         - cinder-tox-py36
         - cinder-rally-task:
             voting: false
-        - tempest-scenario-all:
-            irrelevant-files:
-              - ^(test-|)requirements.txt$
-              - ^.*\.rst$
-              - ^api-ref/.*$
-              - ^cinder/hacking/.*$
-              - ^cinder/locale/.*$
-              - ^cinder/tests/functional.*$
-              - ^cinder/tests/unit.*$
-              - ^contrib/block-box.*$
-              - ^doc/.*$
-              - ^releasenotes/.*$
-              - ^setup.cfg$
-              - ^tools/.*$
-              - ^tox.ini$
     gate:
       jobs:
         - cinder-tox-compliance