ash: when cd fails, say why

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

shell/ash.c

@@ -2748,7 +2748,7 @@ cdcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 	goto docd;
 
  err:
-	ash_msg_and_raise_error("can't cd to %s", dest);
+	ash_msg_and_raise_perror("can't cd to %s", dest);
 	/* NOTREACHED */
  out:
 	if (flags & CD_PRINT)