some shell expansion features into grub-script

tests/util/grub-shell.in

@@ -95,7 +95,7 @@ done
 if [ "x${source}" = x ] ; then
     tmpfile=`mktemp`
     while read; do
-	echo $REPLY >> ${tmpfile}
+	echo "$REPLY" >> ${tmpfile}
     done
     source=${tmpfile}
 fi