tools/testing/selftests/ipc/msgque.c: handle msgget failure return correctly

A failed msgget causes the test to return an uninitialised value in ret.
Assign ret to -errno on error exit.

Signed-off-by: Colin Ian King <[e-mail]>
Acked-by: Davidlohr Bueso <[e-mail]>
Cc: Stanislav Kinsbursky <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

tools/testing/selftests/ipc/msgque.c

···
 
 	msgque.msq_id = msgget(msgque.key, IPC_CREAT | IPC_EXCL | 0666);
 	if (msgque.msq_id == -1) {
+		err = -errno;
 		printf("Can't create queue\n");
 		goto err_out;
 	}