Work on #1582

Deleting a forum doesn't delete the forumpermissions
  * forumpermissions are deleted now

Changed files
  * admin/modules/forum/management.php
    * added delete query for forum permissions
work on #1582

Deleting a forum doesn't delete the forumpermissions
  * Upgrade script removes forumpermissions for deleted forums

Changed files
  * install/resources/upgrade32.php
    * added
    * added delete query
Merge pull request #1605 from Nik101010/fix-1582-feature

fix: Deleting a forum doesn't delete the forumpermissions [#1582]