games/doom: fix idclev cheat in doom2 and final doom

games/doom: fix idclev cheat in doom2 and final doom

[qux]

games/doom: fix idclev cheat in doom2 and final doom

a typo in st_stuff.c:ST_Responder prevents idclev (change level) cheat to work
in doom2 and final doom (gamemode == commercial): episode is set to 0, when
that's invalid, and ST_Responder just returns.
to test, while ingame type idclev, followed by:
. doom1: episode (1-3 or 1-4) then map number (1-9)
. doom2/final doom: map number (1-32)
incidentally, if the last digit typed is 1, the player's weapon will switch to
the fist, because of a different bug (basically kbdproc registering two events
when pressing a key, for 'c' and 'k' case).

diff -Naur a/sys/src/games/doom/st_stuff.c b/sys/src/games/doom/st_stuff.c
--- a/sys/src/games/doom/st_stuff.c	Sun Aug  2 19:57:59 2015
+++ b/sys/src/games/doom/st_stuff.c	Sun Aug 16 19:55:47 2015
@@ -680,7 +680,7 @@

       if (gamemode == commercial)
       {
-	epsd = 0;
+	epsd = 1;
 	map = (buf[0] - '0')*10 + buf[1] - '0';
       }
       else