Fix evaluation for director build parameter.
Fix evaluation for director build parameter.

When director-build is provided validation fails with message:
  msg: The conditional check 'director_build' failed.
  The error was: error while evaluating conditional (director_build):
   'GA' is undefined

Change-Id: I20ce676da8c91fbba13de6cf8dd325882dfa9628

okolisny/InfraRed,okolisny/InfraRed,redhat-openstack/infrared,okolisny/InfraRed,redhat-openstack/infrared,redhat-openstack/infrared