Moved role constraints into model and removed edit deployment

(cherry picked from commit fabb9f67a2a75748423f423989da9841d422ee26)
Merge pull request #34 from vuntz/release/roxy/master

Moved role constraints into model and removed edit deployment
Merge pull request #29 from jgalvez/pull-req-release-roxy-master-c764bee5aeba3d276e615b7dfc09227a4552ba7d

Switch Ceph to use Dumpling, Fix Packages/Repos. [1/1]
Removed the single assignment block from constraints
Merge pull request #35 from tboerger/feature/roxy/fix-constraints

Removed the single assignment block from constraints
Merge pull request #30 from jgalvez/pull-req-release-roxy-master-5458bf315d94064341d4731918096a43df5e57ae

Check for odd number of ceph-mon in proposal [2/2]