Skip running py36 tests on irrelevant files

Local test run definitions were added for running with Python
3.6 as a temporary test. These should eventually go away, but
in the meantime, skip running these on things like docs changes.

Change-Id: Idc42028d4c31d9ee31cdcea11b8749fffa5007b4

.zuul.yaml

@@ -106,6 +106,16 @@
     nodeset: ubuntu-bionic
     vars:
         tox_envlist: functional-py36
+    irrelevant-files:
+      - ^.*\.rst$
+      - ^api-ref/.*$
+      - ^cinder/hacking/.*$
+      - ^cinder/locale/.*$
+      - ^cinder/tests/unit.*$
+      - ^contrib/block-box.*$
+      - ^doc/.*$
+      - ^releasenotes/.*$
+      - ^tools/.*$
 - job:
     # Testing running on bionic
     name: cinder-tox-py36
@@ -113,3 +123,13 @@
     nodeset: ubuntu-bionic
     vars:
         tox_envlist: py36
+    irrelevant-files:
+      - ^.*\.rst$
+      - ^api-ref/.*$
+      - ^cinder/hacking/.*$
+      - ^cinder/locale/.*$
+      - ^cinder/tests/functional.*$
+      - ^contrib/block-box.*$
+      - ^doc/.*$
+      - ^releasenotes/.*$
+      - ^tools/.*$