armbian-next: rootfs: fix: too many bash files included in rootfs B hash, reduce to only what is used to produce rootfs tarball

- otherwise we get rootfs cache misses when working distro-agnostic and others, which are not part of rootfs code

lib/functions/rootfs/create-cache.sh

@@ -30,7 +30,7 @@ function calculate_rootfs_cache_id() {
 
 	# get the hashes of the lib/ bash sources involved...
 	declare hash_files="undetermined"
-	calculate_hash_for_files "${SRC}"/lib/functions/rootfs/*.sh # the whole dir
+	calculate_hash_for_files "${SRC}"/lib/functions/rootfs/create-cache.sh "${SRC}"/lib/functions/rootfs/rootfs-create.sh
 	declare bash_hash="${hash_files}"
 	declare bash_hash_short="${bash_hash:0:6}"