Add a .gitreview file.

Change-Id: I2ff3a4f19829aec841235326597fb8793c5065f8
Reviewed-on: https://review.openstack.org/20724
Reviewed-by: Elizabeth Krumbach <lyz@princessleia.com>
Approved: Dan Prince <dprince@redhat.com>
Reviewed-by: Dan Prince <dprince@redhat.com>
Tested-by: Jenkins