Fix typo in the Lake random map script.

This was SVN commit r14643.

binaries/data/mods/public/maps/random/lake.js

@@ -298,7 +298,7 @@ createLayeredPatches(
 log("Creating grass patches...");
 createPatches(
  [scaleByMapSize(2, 4), scaleByMapSize(3, 7), scaleByMapSize(5, 15)],
- tTie4Terrain,
+ tTier4Terrain,
  avoidClasses(clWater, 3, clForest, 0, clHill, 0, clDirt, 5, clPlayer, 12)
 );
 
@@ -399,4 +399,4 @@ setWaterWaviness(10);
 
 // Export map data
 
-ExportMap();
+ExportMap();