Expose region name to UI

Enable support for custom region name. This name is use to register the
keystone endpoint. It doesn't support multiple endpoints for different
regions.

related to: https://bugzilla.novell.com/show_bug.cgi?id=896481
I agree. Updated the revision to 20 in https://github.com/toabctl/barclamp-keystone/commit/42676eecca35d93313f2d7c07cc6d0ff94a1c213