integration: Copy distro-sync from main Dockerfile

Over in #1607
I actually *just* deduplicated this code, but that isn't
ready to merge yet.

Signed-off-by: Colin Walters <walters@verbum.org>

Author: cgwalters

tests/build.sh

@@ -34,6 +34,7 @@ case \$ID in
     centos|rhel) dnf config-manager --set-enabled crb;;
     fedora) dnf -y install dnf-utils 'dnf5-command(builddep)';;
 esac
+dnf -y distro-sync ostree{,-libs} systemd
 dnf -y builddep contrib/packaging/bootc.spec
 dnf -y install git-core
 EORUN