Remove the redundant verification in OAuth1 authorization

The code verify the assignment filtered by `user_id` after
verifying the assignment filtered by `user_id` and `project_id`.

The latter should be a subset of the former.

Change-Id: I056f543a1dfbd0ad8965cdd37bb986a665711ab7

keystone/oauth1/controllers.py

@@ -394,16 +394,6 @@ class OAuthControllerV3(controller.V3Controller):
         # create list of just the id's for the backend
         role_ids = list(authed_roles)
 
-        # verify the user has the project too
-        req_project_id = req_token['requested_project_id']
-        user_projects = self.assignment_api.list_projects_for_user(user_id)
-        for user_project in user_projects:
-            if user_project['id'] == req_project_id:
-                break
-        else:
-            msg = _("User is not a member of the requested project")
-            raise exception.Unauthorized(message=msg)
-
         # finally authorize the token
         authed_token = self.oauth_api.authorize_request_token(
             request_token_id, user_id, role_ids)