Swfdec version for 2.24

["Benjamin Otte" <otte gnome org>]

Hey,

As Swfdec tracks GNOME development and provides a new major release
for every new GNOME release, we will release Swfdec 0.8 to go with it.
I hope updating the external dependencies is fine here.
Today Swfdec 0.7.4 was released and I updated the swfdec-gnome package
to not depend on Swfdec 0.6 anymore but track the 0.7 releases. I've
updated the jhbuild moduleset accordingly already.

Cheers,
Benjamin