fix for 0006059: MySQL 4.1.1 or later by default uses long passwords which don't work with php4

• added version check and warning in install.php
  fix for 0006060: Should have option to turn on debugging for ADOdb on initial install connection
• print database error message for all failures
  fixed missing page header if database connect fails

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@3766 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9