Bug#898305: gnome-keysign: fix dependency on gstreamer1.0-gtk3

[Jeremy Bicha]

Package: gnome-keysign
Version: 0.9.7-1
Severity: serious

gnome-keysign depends on the non-existent gstreamer1.0-gtk. I think
you want gstreamer1.0-gtk3 instead.

Thanks,
Jeremy Bicha