Fix '[: /dev/md: unknown operand' for LiveCD boots.

git-svn-id: svn+ssh://svn.gentoo.org/var/svnroot/genkernel/trunk@264 67a159dc-881f-0410-a524-ba9dfbe2cb84

generic/initrd.scripts

@@ -510,6 +510,8 @@ cdupdate() {
 }
 
 setup_md_device() {
+	[ -z "${REAL_ROOT}" ] && return # LiveCD
+
 	if [ `echo ${REAL_ROOT}|sed -e 's#\(/dev/md\)[[:digit:]]\+#\1#'` = "/dev/md" ]
 	then
 		good_msg 'Detected real_root as a md device. Setting up the device node...'