gnome-desktop for GNOME 3.22 will depend on libudev

[Bastien Nocera <hadess hadess net>]

From https://bugzilla.gnome.org/show_bug.cgi?id=590059

"
hwdb has its own database which it compiles to binary, so that:
1) initialisation is practically free
See https://git.gnome.org/browse/gnome-settings-daemon/commit/gnome-set
tings-daemon/gnome-settings-
manager.c?id=d8c158e74caea048dea5a38232bd87c1c7a78a70
2) lookups are also quick, as they use a binary DB
3) we don't have to maintain our own copy of the database
4) allows model lookup rather than simply vendor lookup, when the
   database contains that information
"

jhbuild has been updated to reflect the new dependencies. Non-Linux
OSes should revert this patch in their 3.22 releases.

libudev was already a dependency of gnome-bluetooth, which uses it to
lookup vendor names from udev/hwdb's OUI database.

Cheers