little fix for _get_user_tenants_roles_by_db
little fix for _get_user_tenants_roles_by_db

This fix solves ''unhashable type dict' error in
_get_user_tenants_roles_by_db method of Identity CF resource by
checking keystone db version and correcting user roles data format.

MirantisWorkloadMobility/CloudFerry,mgrygoriev/CloudFerry,SVilgelm/CloudFerry,MirantisWorkloadMobility/CloudFerry,SVilgelm/CloudFerry,SVilgelm/CloudFerry,mgrygoriev/CloudFerry,MirantisWorkloadMobility/CloudFerry,MirantisWorkloadMobility/CloudFerry,SVilgelm/CloudFerry,mgrygoriev/CloudFerry,mgrygoriev/CloudFerry