Revert "Add frosted ice to ice-melt flag."

Re-Un-Fixes WORLDGUARD-3745 because apparently this isn't what was
requested.

worldguard-legacy/src/main/java/com/sk89q/worldguard/bukkit/listener/WorldGuardBlockListener.java

@@ -624,7 +624,6 @@ public void onBlockFade(BlockFadeEvent event) {
 
         switch (event.getBlock().getTypeId()) {
         case BlockID.ICE:
-        case BlockID.FROSTED_ICE:
             if (wcfg.disableIceMelting) {
                 event.setCancelled(true);
                 return;