Created attachment 349246 [details] [review]
gobject: remove duplicate GType sanity check

As per discussion on IRC with ebassi.

This is going to be checked again by g_object_new_with_properties()
and g_object_new_valist() anyway, so might just as well leave it
to those functions to do the check and only do it once. It doesn't
matter which function emits the critical warning in the end either,
as one has to look at a stack trace to find out what code triggered
it in any case.