libotutil: Make use of GBytes in ot_variant_read()
libotutil: Make use of GBytes in ot_variant_read()

This is just cleaner; we avoid using GObject data, etc.

https://bugzilla.gnome.org/show_bug.cgi?id=706031

resin-io/ostree,resin-io/ostree,leandrosansilva/ostree,GNOME/ostree,gatispaeglis/ostree,resin-io/ostree,leandrosansilva/ostree,gatispaeglis/ostree,GNOME/ostree,resin-io/ostree,sujitfulse/ostree,sujitfulse/ostree,sujitfulse/ostree,gatispaeglis/ostree,GNOME/ostree,GNOME/ostree,sujitfulse/ostree,leandrosansilva/ostree,gatispaeglis/ostree,leandrosansilva/ostree,leandrosansilva/ostree,resin-io/ostree,gatispaeglis/ostree,GNOME/ostree,sujitfulse/ostree,gatispaeglis/ostree