Fix the openshift-ansible CI breakage

A change in openshift-ansible has broken our CI (and deployments):

https://travis-ci.org/openshift/openshift-ansible-contrib/jobs/301329799

```
TASK [template_service_broker : Reconcile with RBAC file]
**********************
Monday 13 November 2017  11:16:35 +0000 (0:00:00.818)       0:15:06.296
*******
fatal: [master-0.openshift-1829.example.com]: FAILED! => {"changed":
true, "cmd": "oc process -f
\"/tmp/tsb-ansible-C1kuTw/rbac-template.yaml\" | oc auth reconcile -f
-", "delta": "0:00:00.355587", "end": "2017-11-13 11:16:36.444135",
"failed": true, "rc": 1, "start": "2017-11-13 11:16:36.088548",
"stderr": "Error: unknown shorthand flag: 'f' in -f\n\n\nUsage:\n  oc
auth [options]\n\nAvailable Commands:\n  can-i       Check whether an
action is allowed\n\nUse \"oc <command> --help\" for more information
about a given command.\nUse \"oc options\" for a list of global
command-line options (applies to all commands).", "stderr_lines":
["Error: unknown shorthand flag: 'f' in -f", "", "", "Usage:", "  oc
auth [options]", "", "Available Commands:", "  can-i       Check whether
an action is allowed", "", "Use \"oc <command> --help\" for more
information about a given command.", "Use \"oc options\" for a list of
global command-line options (applies to all commands)."], "stdout": "",
"stdout_lines": []}
```

The openshift-ansible issue tracking this:

https://github.com/openshift/openshift-ansible/issues/6086

The issue appears to be caused by the
ad977b701124f5e134e8c2a0cbc6e907ce177366 commit.

And it's not present in the previous commit, i.e.:

56b529e493a5f55ecfc75bc20a807a3d73e03507 Fix examples image streams
tag: openshift-ansible-3.7.2-1-8-g56b529e

So we switch the CI to use that until the upstream issue is resolved.

.travis.yml

@@ -15,7 +15,7 @@ python:
 env:
   global:
     - CI_CONCURRENT_JOBS=1
-    - OPENSHIFT_ANSIBLE_COMMIT=master
+    - OPENSHIFT_ANSIBLE_COMMIT=openshift-ansible-3.7.2-1-8-g56b529e
   matrix:
     - RUN_OPENSTACK_CI=false
     - RUN_OPENSTACK_CI=true