updated the location of the global translations

Author: fabpot

book/translation.rst

@@ -273,7 +273,7 @@ Symfony2 looks for message files (i.e. translations) in two locations:
  live in the ``Resources/translations/`` directory of the bundle;
 
 * To override any bundle translations, place message files in the
- ``app/translations`` directory.
+ ``app/Resources/translations`` directory.
 
 The filename of the translations is also important as Symfony2 uses a convention
 to determine details about the translations. Each message file must be named