[Kubuntu] File associations should not be changed when application registers mime types

When an application is installed which uses the standard tools (xdg-mime install and xdg-desktop-menu install) to register shortcuts and mime types, Kubuntu's default types are sometimes changed. Neither of these commands should set the default association for a mime type unless it was previously unset. However, Kubuntu will change currently-set mime types when an application registers that it can handle them.

Thanks for looking into this.

✈demios:~$ lsb_release -rd
Description: Ubuntu 11.04
Release: 11.04
✈demios:~$