Don't run DSVM tests for doc changes

Don't waste resources running the dsvm-functional tests on doc-only
changes.

Change-Id: Ie18427499c170ee315181040eaa0943f3fefed08

.zuul.yaml

@@ -9,6 +9,10 @@
       - openstack-infra/devstack-gate
       - openstack/cinder
       - openstack/python-cinderclient
+    irrelevant-files:
+      - ^.*\.rst$
+      - ^doc/.*$
+      - ^releasenotes/.*$
 
 - job:
     name: cinderclient-dsvm-functional-identity-v3-only
@@ -21,7 +25,10 @@
       - openstack-infra/devstack-gate
       - openstack/cinder
       - openstack/python-cinderclient
-
+    irrelevant-files:
+      - ^.*\.rst$
+      - ^doc/.*$
+      - ^releasenotes/.*$
 
 - project:
     templates: