libostree: Add a better error if we fail to read keyring directory
libostree: Add a better error if we fail to read keyring directory

I had accidentally put it in the -devel package and not noticed.

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