fault_inject: use SIGKILL instead of BUG() to kill itself

If a process calls BUG(), it genereates a core file and
we get a false warning from abrtd.
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/cr-dump.c

@@ -1286,7 +1286,7 @@ static int dump_one_task(struct pstree_item *item)
 
 	if (fault_injected(FI_DUMP_EARLY)) {
 		pr_info("fault: CRIU sudden detach\n");
-		BUG();
+		kill(getpid(), SIGKILL);
 	}
 
 	if (root_ns_mask & CLONE_NEWPID && root_item == item) {

criu/cr-restore.c

@@ -1615,7 +1615,7 @@ static int restore_task_with_children(void *_arg)
 
 	if (fault_injected(FI_RESTORE_ROOT_ONLY)) {
 		pr_info("fault: Restore root task failure!\n");
-		BUG();
+		kill(getpid(), SIGKILL);
 	}
 
 	timing_start(TIME_FORK);

criu/files-reg.c

@@ -1609,7 +1609,7 @@ int open_path(struct file_desc *d,
 	if (rfi->remap) {
 		if (fault_injected(FI_RESTORE_OPEN_LINK_REMAP)) {
 			pr_info("fault: Open link-remap failure!\n");
-			BUG();
+			kill(getpid(), SIGKILL);
 		}
 
 		mutex_lock(remap_open_lock);