Moved role constraints into model and removed edit deployment

(cherry picked from commit bdf3e3bed88227fe74fb1f046e572a0a1c3487a6)
Merge pull request #42 from vuntz/release/roxy/master

Moved role constraints into model and removed edit deployment
Removed the single assignment block from constraints
Merge pull request #43 from tboerger/feature/roxy/fix-constraints

Removed the single assignment block from constraints
added keystone + haproxy patch (https://github.com/crowbar/barclamp-heat/pull/39)
HAProxy support for heat-api*

adapt helper and model to prepare cluster info

db password must not be created in the cookbook, but in crowbar
(so that it is common for the cluster nodes)

increased schema-revision

use the library functions for shared code