Add lock management and call parent.

def _call_command(self, name, *args, **kwargs):
        """
        Add lock management and call parent.
        """
        meth = super(RedisField, self)._call_command
        if self.indexable and name in self.available_modifiers:
            with FieldLock(self):
                try:
                    result = meth(name, *args, **kwargs)
                except:
                    self._rollback_indexes()
                    raise
                else:
                    return result
                finally:
                    self._reset_indexes_caches()
        else:
            return meth(name, *args, **kwargs)