500 error when rename user without personal repo

Created by: erroric

This bug occurs if username directory (ex. uname123) is not exists in /home/git/repositories

RuntimeError (Namespace move error /home/git/repositories/uname123 /home/git/repositories/username123):
  app/models/namespace.rb:79:in `move_dir'
  app/observers/user_observer.rb:15:in `after_save'
  app/controllers/admin/users_controller.rb:89:in `block in update'
  app/controllers/admin/users_controller.rb:88:in `update'