Remove deprecated bits from virtualbox.desktop

[PeladoFeo]

virtualbox.desktop (/usr/share/applications/virtualbox.desktop) ships with the following categories:

Categories=Emulator;System;X-MandrivaLinux-System;Application;

The category "Application" does not exist and should be dropped. The category "X-MandrivaLinux-System" can safely be dropped as it's overridden by "System".

Reference: ​http://standards.freedesktop.org/menu-spec/menu-spec-1.0.html

Additionally, the desktop file ships with a "DocPath" key:

DocPath=​file:///usr/share/doc/virtualbox/UserManual.pdf

This key does not exist and has no effect. It should either be dropped, or be replaced by an "extension" key, such as X-Gnome-DocPath (which is the only one that exists that I could find).

I would send a patch but I can't get svn sorted out. This is an easy change, so anyone else please pick it up. Thank you.

[PeladoFeo]

By X-Gnome-DocPath I meant X-GNOME-DocPath

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.