Fix up again sql connection as in persistent mode, closing the sql connection doesn't close or terminate the existing connection.  This means, mysql fills up with users which may be blocked eventually.

git-svn-id: https://svn.code.sf.net/p/freeghost/code/trunk@2641 71f96598-fa45-0410-b640-bcd6f8691b32
Merge svn with dev-branch