Fix device node deletion in OCI rootfs tarballs (LP:#1930686)

The bionic tarballs created for the minimized OCI project do contain
files in /dev/ . That's not wanted and might cause problems[0] so do
remove these files.

[0] https://github.com/tianon/docker-brew-ubuntu-core/issues/62

debian/changelog

@@ -1,3 +1,10 @@
+livecd-rootfs (2.525.55) UNRELEASED; urgency=medium
+
+  * Remove device node files in /dev from rootfs tarball for oci project
+    builds (LP: #1930686)
+
+ -- Thomas Bechtold <thomas.bechtold@canonical.com>  Thu, 03 Jun 2021 10:27:32 +0200
+
 livecd-rootfs (2.525.54) bionic; urgency=medium
 
   * Add grub config to produce console output to allow buildd vm images to

live-build/auto/build

@@ -482,7 +482,7 @@ EOF
 	rm -f chroot/var/cache/debconf/*-old chroot/var/lib/dpkg/*-old
 	Chroot chroot apt clean
 	# For the docker images we remove even more stuff.
-	if [ "${PROJECT}:${SUBPROJECT:-}" = "ubuntu-base:minimized" ]; then
+	if [ "${PROJECT}:${SUBPROJECT:-}" = "ubuntu-base:minimized" ] || [ "${PROJECT}:${SUBPROJECT:-}" = "ubuntu-oci:minimized" ]; then
 		# Remove apt lists (that are currently removed downstream
 		# anyway)
 		rm -rf chroot/var/lib/apt/lists/*