Fix ceph.repo so it uses URI value.
Fix ceph.repo so it uses URI value.

Basically some weird cases where ceph-releases would be pointing
to the wrong branch/build when two branches had the same sha1.
This fixes that.

Signed-off-by: Sandon Van Ness <a38d61b815b8053a15c463c80449b5c080334ec7@inktank.com>

SUSE/teuthology,michaelsevilla/teuthology,yghannam/teuthology,zhouyuan/teuthology,ktdreyer/teuthology,robbat2/teuthology,tchaikov/teuthology,dmick/teuthology,caibo2014/teuthology,ktdreyer/teuthology,ceph/teuthology,yghannam/teuthology,dmick/teuthology,robbat2/teuthology,SUSE/teuthology,SUSE/teuthology,ivotron/teuthology,caibo2014/teuthology,zhouyuan/teuthology,ivotron/teuthology,t-miyamae/teuthology,dreamhost/teuthology,tchaikov/teuthology,michaelsevilla/teuthology,dmick/teuthology,dreamhost/teuthology,t-miyamae/teuthology,ceph/teuthology