• core/bug_api.php
  (bug_cache_row): cache the fact that the bug doesn't exist
  (bug_text_cache_row): cache the fact that the bug text doesn't exist

• core/project_api.php
  (project_cache_row): cache the fact that the project doesn't exist

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@1842 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9