Skip V-38620 (chrony) in gate

The OpenStack CI runs ntpd in the gate images and this causes chrony
to fail on startup. This patch skips V-38620 so that chrony won't
cause gate failures.

Closes-Bug: 1629936
Manual backport of: I0c67241c0725621715877e728a6c6c17d771a596
Change-Id: I1420049f7146382261712328fb55ac10274aef11

tox.ini

@@ -171,12 +171,14 @@ setenv =
 # NOTE(odyssey4me): We have to skip V-38462 as openstack-infra are now building
 #                   images with apt config Apt::Get::AllowUnauthenticated set
 #                   to true.
+# NOTE(mhayden): Skipping V-38620 since chrony cannot start with ntpd
+#                running in the gate images.
 commands =
     {[testenv:ansible]commands}
     ansible-playbook -i {toxinidir}/tests/inventory \
                      -e "rolename={toxinidir}" \
                      -e "install_test_packages=True" \
-                     --skip-tag V-38462 \
+                     --skip-tag V-38462,V-38620 \
                      {toxinidir}/tests/test.yml -vvvv