fix history display for:
0007364: Custom field visible in history independent from user role
0007345: Bug history shows records of private notes.
0003375: Bughistory bypasses security on custom fields
0007317: Issue History
0005050: Custom Fields display in bug history
0006726: Access level read in Issue History not used
0006724: Issue history ignores custom field read/write access
0004988: Private bug notes/relationships in "issue history"

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@4185 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9