fix minor memory leak

src/slurmctld/node_scheduler.c

@@ -1742,6 +1742,8 @@ extern void re_kill_job(struct job_record *job_ptr)
 
 	if (agent_args->node_count == 0) {
 		xfree(kill_job);
+		if(agent_args->hostlist)
+			hostlist_destroy(agent_args->hostlist);
 		xfree(agent_args);
 		hostlist_destroy(kill_hostlist);
 		return;