Once in a month, when the moon is full, killall mistakenly considers

living process as a zombie and refuses to kill it. The cause is that
the code masks ki_stat with SZOMB to compare with SZOMB, but ki_stat
is not a mask.

Possibly reported by:	cperciva
MFC after:	3 days

usr.bin/killall/killall.c

@@ -319,7 +319,7 @@ main(int ac, char **av)
 	mypid = getpid();
 
 	for (i = 0; i < nprocs; i++) {
-		if ((procs[i].ki_stat & SZOMB) == SZOMB && !zflag)
+		if (procs[i].ki_stat == SZOMB && !zflag)
 			continue;
 		thispid = procs[i].ki_pid;
 		strlcpy(thiscmd, procs[i].ki_comm, sizeof(thiscmd));