gnome-disk-utility: disable scrollkeeper

scrollkeeper isn't packaged neither in oe.dev, nor in any oe-core based
layer. Disable scrollkeeper in gnome-disk-utils.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>