Stops the cpulimit process.

def _stop_cpulimit(self):
        """
        Stops the cpulimit process.
        """

        if self._cpulimit_process and self._cpulimit_process.returncode is None:
            self._cpulimit_process.kill()
            try:
                self._process.wait(3)
            except subprocess.TimeoutExpired:
                log.error("Could not kill cpulimit process {}".format(self._cpulimit_process.pid))