Fix the type of the TpStreamTubeConnection::closed signal
Fix the type of the TpStreamTubeConnection::closed signal

python-gobject can't bind G_TYPE_POINTER.

This seems to be save from an API/ABI pov according to GLib gurus,
we'll just copy the GError instead of passing the same pointer:

Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib