further fix for 0005948: user_pref initialization makes many database queries

• mapping of structure to defaults is not simple, added translation table
• added initialization of non-existent parameters

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@3673 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9