Fixed 0003597: custom fields names are not translaten in email (thanks to yarik123).

M core/email_api.php

• (email_build_bug_message): Translate the custom field names.

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@2379 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9