The aim of this commit is to change the prefix for auto-generated names from a
configuration option to a language string. This will allow multi-lingual
support. However, there is currently no way to turn this feature OFF, which
shouldn't be a problem.

• config_defaults_inc.php:

• Removed the $g_prefix_for_deleted_users.

• doc/Changelog:

• Updated the change log to change the new config option to an enhancement.

• core/user_api.php
  (user_get_name): Use the lang string rather than the config, and drop the
  usage of the account no longer exists string.

• lang/strings_english.txt
  Drop the "account no longer exists" string, and add the prefix for deleted
  users string.

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@1754 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9