initrd.d: move is_livecd() back to 00-common.sh to avoid circular deps

defaults/initrd.d/00-common.sh

@@ -5,6 +5,11 @@ is_nfs() {
     return 1
 }
 
+is_livecd() {
+    [ "${CDROOT}" = "1" ] && return 0
+    return 1
+}
+
 good_msg() {
     [ -n "${QUIET}" ] && [ -z "${DEBUG}" ] && return 0
 

defaults/initrd.d/00-livecd.sh

@@ -268,11 +268,6 @@ _livecd_mount_copy_content() {
     mount --bind "${CDROOT_PATH}" "${new_cdroot}"
 }
 
-is_livecd() {
-    [ "${CDROOT}" = "1" ] && return 0
-    return 1
-}
-
 media_find() {
     # $1 = mount dir name / media name
     # $2 = recognition file