Fix a segfault when selecting a non-existent game entry to watch. Found by blackpenguin.

git-svn-id: svn://katsu.triplehelix.org/dgamelaunch/trunk@521 db0b04b0-f4d1-0310-9a6d-de3e77497b0e

TODO

@@ -1,3 +1,10 @@
+-when exiting from watching a player, move the cursor to the last line
+ of the screen before enabling the ncurses mode; so when we exit dgl,
+ the watched player's game is all visible and the menu prompt doesn't
+ mess it up.
+-watching menu will hilight the first matching username... what if we have
+ more than one game installed, and someone's playing more than one at the
+ same time?  Should also save game#, not just the username.
 -allow admin to disabling the 'm' mail key in ttyplay.
 -update README
 -maybe allow something like changed_menu="[Updated %d]" config option  and

dgamelaunch.c

@@ -583,7 +583,7 @@ inprogressmenu (int gameid)
 	    if (strchr(selectorchars, menuchoice) && (len > 0)) {
 		int sidx = strchr(selectorchars, menuchoice) - selectorchars;
 
-		if (sidx > max_height) {
+		if ((sidx > max_height) || (sidx >= len)) {
 		    selected = -1;
 		    break;
 		}