[lib] Fix privacy issues present in Ubuntu 12.10+

By default, starting with Ubuntu 12.10, each time the user starts
typing in `Dash` (to open an application or search for a file on the
computer), the search terms get sent to a variety of third parties,
some of which advertise to the user.

This commit adds some settings that disable the parts of Ubuntu that
are invasive to the user's privacy.

Note: This privacy problem only affects Unity. Other desktop
environments (e.g.: GNOME) and other Ubuntu derivatives (e.g.: Linux
Mint, Xubuntu, Kubuntu) are not affected.

Ref: https://fixubuntu.com/