If a deployer sets the boolean vars to 'yes', 'no' or
other equivalent booleans valid for ansible, the glance
services will currently use those in the .conf files
and it will break.
This patch ensures that we cast the output into the
.conf files properly so that regardless of the input,
the output is correct.
The tests are adjusted to deliberately use one of the
Ansible boolean values instead of a python boolean to
validate that this works.
Change-Id: I267b97da618bbda05140d2a0332798fc77db06a5
4e0c72cfe9