dist-packaging: Don't delete 91-ostree.preset, do clean old rpms/sources
dist-packaging: Don't delete 91-ostree.preset, do clean old rpms/sources

We have to copy the sources to avoid rpmbuild deleting them.  But on
the other hand there's no reason for old sources to stick around.

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