Added attribute mapping service

bp/role-mapping-service-keystone

Change-Id: Idf0c1e5bb0af6e5dc5bd34495ee35ece5572125b
Merge branch 'bp/role-mapping-service-keystone' of https://github.com/kwssiu/keystone into bp/role-mapping-service-keystone

Conflicts:
	keystone/mapping/__init__.py
	keystone/mapping/backends/sql.py
	keystone/mapping/controllers.py
	keystone/mapping/core.py
	keystone/service.py
	tests/test_sql_upgrade.py
	tests/test_v3_mapping.py

Change-Id: I9611ad55551aeef5084ef2b46b8fe1598b677504