Use region from keystone settings

The keystone barclamp got the possibility to set a custom region
name. This name must be used by other barclamps as well.

related to: https://bugzilla.novell.com/show_bug.cgi?id=896481

(cherry picked from commit cfdd9b6de01c511f19407153d232c014e3d5a473)
Merge pull request #101 from toabctl/c4-region-support

Use region from keystone settings