Initialize sequence numbers to 0 in seminit() instead of using whatever

garbage happens to be in memory. This did not seem to cause any problems
except making semaphore ID's unpredictable (and ugly in ipcs(1) output).

sys/kern/sysv_sem.c

@@ -198,6 +198,7 @@ seminit(void)
 	for (i = 0; i < seminfo.semmni; i++) {
 		sema[i].sem_base = 0;
 		sema[i].sem_perm.mode = 0;
+		sema[i].sem_perm.seq = 0;
 	}
 	for (i = 0; i < seminfo.semmni; i++)
 		mtx_init(&sema_mtx[i], "semid", NULL, MTX_DEF);