tweaks: add gconf-sanity for providing /usr/libexec/gconf-sanity-check-2

This is a workaround for the gconf/gtk2 dependency loop

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
angstrom-packagegroup-gnome: drag in gconf-sanity

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>