Use previously retrieved destination root FS label

Now labels are retrieved for all destination partitions, there is no
longer any point in separately retrieving the destination root label,
just use the previously retrieved label.

Author: matthijskooijman

rpi-clone

@@ -1769,12 +1769,7 @@ fi
 
 rm -f $clone/etc/udev/rules.d/70-persistent-net.rules
 
-dst_root_vol_name=`e2label $dst_root_dev`
-
-if [ "$dst_root_vol_name" = "" ]
-then
-	dst_root_vol_name="no label"
-fi
+dst_root_vol_name=${dst_label[$root_part_num]}
 
 if ((have_grub))
 then