Inject nohup to make sure that bkill executes after ert dies

src/ert/scheduler/lsf_driver.py

@@ -414,7 +414,7 @@ async def kill(self, iens: int) -> None:
                 return_on_msgs=(JOB_ALREADY_FINISHED_BKILL_MSG),
             )
             await asyncio.create_subprocess_shell(
-                f"sleep {self._sleep_time_between_bkills}; {self._bkill_cmd} -s SIGKILL {job_id}",
+                f"nohup sh -c sleep {self._sleep_time_between_bkills}; {self._bkill_cmd} -s SIGKILL {job_id}' &",
                 start_new_session=True,
                 stdout=asyncio.subprocess.DEVNULL,
                 stderr=asyncio.subprocess.DEVNULL,