Prevent array index bounds problems if isOccupiedPlayer gets called

with -1 (I saw it happen entering a sword game as a watcher).


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@3613 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/parlor/game/data/GameObject.java

@@ -179,7 +179,7 @@ public class GameObject extends PlaceObject
      */
     public boolean isOccupiedPlayer (int pidx)
     {
-        return (players[pidx] != null);
+        return (pidx >= 0 && pidx < players.length) && (players[pidx] != null);
     }
 
     /**