core: Fix inverted conditional in GPG checking
core: Fix inverted conditional in GPG checking

GNOME/ostree,leandrosansilva/ostree,sujitfulse/ostree,GNOME/ostree,leandrosansilva/ostree,GNOME/ostree,sujitfulse/ostree,gatispaeglis/ostree,GNOME/ostree,leandrosansilva/ostree,GNOME/ostree,gatispaeglis/ostree,gatispaeglis/ostree,sujitfulse/ostree,gatispaeglis/ostree,sujitfulse/ostree,leandrosansilva/ostree,gatispaeglis/ostree,sujitfulse/ostree,leandrosansilva/ostree,gatispaeglis/ostree