Fix 0003097: App Error 700 in project_api.php when viewing certain bugs.

M core/history_api.php

• (history_get_events_array): Check that the old/new project exists before attempting to get its name.

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@2194 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9