collection-view: Reflect GTK+ VAPI changes
collection-view: Reflect GTK+ VAPI changes

Assign a Gdk.Rectangle instead of a Cairo.RectangleInt to
Gtk.Popover.pointing_to in method launch_context_popover_for_path()
in order to reflect changes in GTK+'s VAPI.

https://bugzilla.gnome.org/show_bug.cgi?id=749914

vbenes/gnome-boxes,vbenes/gnome-boxes