otutil: Correctly add ref to bytes when creating GVariant
otutil: Correctly add ref to bytes when creating GVariant

This one went undiscovered for a while because it turned out we
weren't using it...

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