core: Initialize variables in fsck
core: Initialize variables in fsck

Otherwise we segfault on an unhandled filename.

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