doc: A long overdue manpage update
doc: A long overdue manpage update

Ok, just a little one, but still.  I actually updated documentation!

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