Source devtest_variables in tripleo-cd.

New file, needs to be included. Oops :)

Change-Id: Iad1e0e92ce9044ffcb1f86ab20c2a52888038215
Disable libvirt file injection.

Its bad for performance and reliability and generally terrible.

It's also being disabled by default upstream.

Change-Id: I24f1d399c7068567c1f18f50e69eb25e52b485b9
Implements: blueprint disable-file-injection-by-default
Force UTF-8 charset and collation for MySQL

Default is latin1/latin1_swedish_ci. We do not want either of those. The
config change we're making will ignore anything clients specify and just
use UTF-8 for everything on the server.

Change-Id: I4dfd485ecb0d55b2230a6072f45552c20fee043c