Add a unit test for a nonexistent ceph branch
Add a unit test for a nonexistent ceph branch

This test checks whether scheduling fails when an invalid ceph branch is
specified

Signed-off-by: Zack Cerza <d7cdf09fc0f0426e98c9978ee42da5d61fa54986@redhat.com>

SUSE/teuthology,dmick/teuthology,dmick/teuthology,ktdreyer/teuthology,ceph/teuthology,ceph/teuthology,ktdreyer/teuthology,SUSE/teuthology,dmick/teuthology,SUSE/teuthology