Bump ansible to 1.9.2

Ansible 1.9.2 contains the fix needed for docker-py >1.2.0

This is needed for some gate reasons, but it is also a good version
bump because it fixes a few issues with delegate_to.

Change-Id: Iafbabb3b0232620849d0548c5cd9d8d316c2b0f3
backport: liberty
Partially-Implements: blueprint functional-testing-gate