mailscanner, allow de-installation of the package (on 2.2 ?).

solves: [ PHP ERROR Type:64, File:/etc/inc/globals.inc, Line: 176, Message: Cannot redeclare platform_booting() (previously declared in /etc/inc/globals.inc:168)]
Remove obsolete validation check.
Merge pull request #754 from bmeeks8/snort-2.9.7.0-v3.2
Bump package revision due to last changes
Merge pull request #750 from PiBa-NL/mailscanner