Do not use self in classmethod

cls should be used in classmethod, instead of self.

Change-Id: I3b5bb805a79b25050ed459f85ad25681171aa743

keystone/assignment/backends/sql.py

@@ -43,7 +43,7 @@ class AssignmentType(object):
 class Assignment(base.AssignmentDriverBase):
 
     @classmethod
-    def default_role_driver(self):
+    def default_role_driver(cls):
         return 'sql'
 
     def create_grant(self, role_id, user_id=None, group_id=None,

keystone/cmd/cli.py

@@ -252,7 +252,7 @@ class DbSync(BaseApp):
         return parser
 
     @classmethod
-    def check_db_sync_status(self):
+    def check_db_sync_status(cls):
         status = 0
         try:
             expand_version = upgrades.get_db_version(repo='expand_repo')