move skip_lb_stage to config

debian/changelog

@@ -1,4 +1,4 @@
-livecd-rootfs (2.505~ppa1) bionic; urgency=medium
+livecd-rootfs (2.505~ppa2) bionic; urgency=medium
 
   * Move casper from filesystem.squashfs to installer.squashfs. 
 

live-build/auto/config

@@ -116,6 +116,12 @@ if [ -z "${IMAGEFORMAT:-}" ]; then
 	esac
 fi
 
+skip_lb_stage() {
+	STAGE="$1"
+	mkdir -p .build
+	touch ".build/$STAGE"
+}
+
 case $IMAGEFORMAT in
 	ext2|ext3|ext4)
 		OPTS="${OPTS:+$OPTS }--initramfs none --chroot-filesystem $IMAGEFORMAT"

live-build/functions

@@ -330,12 +330,6 @@ undivert_grub() {
 		--rename /usr/bin/systemd-detect-virt
 }
 
-skip_lb_stage() {
-	STAGE="$1"
-	mkdir -p .build
-	touch ".build/$STAGE"
-}
-
 recreate_initramfs() {
 	# Regenerate the initramfs by running update-initramfs in the
 	# chroot at $1 and copying the generated initramfs