Fixed 0003495: Warning even if administrator account is disabled

M login_page.php

• The warning for administrator account was displayed if the account exists with the default password. It didn't check for the enabled flag.

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@2280 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9