Disable building of adblock again, it's still not ready

extensions/wscript_build

@@ -6,6 +6,9 @@ import os
 
 extensions = os.listdir ('extensions')
 for extension in extensions:
+    # Adblock is incomplete and not ready for release
+    if extension == 'adblock.c':
+        continue
     folder = 'extensions' + os.sep + extension
     if os.path.isdir (folder):
         files = os.listdir (folder)