Merge pull request #2987 from sdodson/etcd3015

The next registry.access.redhat.com/rhel7/etcd image will be 3.0.15 not 3.0.14

playbooks/common/openshift-cluster/upgrades/etcd/upgrade.yml

@@ -75,7 +75,7 @@
   hosts: etcd_hosts_to_upgrade
   serial: 1
   vars:
-    upgrade_version: 3.0.14
+    upgrade_version: 3.0.15
   tasks:
   - include: containerized_tasks.yml
     when: etcd_container_version.stdout | default('99') | version_compare('3.0','<') and openshift.common.is_containerized | bool