AK3+Backend: cleanups, update *_line functions

- touch up a couple pesky minor things
- add global scope to replace_line and remove_line so they match replace_string, and can now work on all matches found in a file

META-INF/com/google/android/update-binary

@@ -90,7 +90,7 @@ umount_apex() {
   local dest loop;
   for dest in $($BB find /apex -type d -mindepth 1 -maxdepth 1); do
     if [ -f $dest.img ]; then
-      loop=$($BB mount | $BB grep $dest | $BB cut -d" " -f1);
+      loop=$($BB mount | $BB grep $dest | $BB cut -d\  -f1);
     fi;
     ($BB umount -l $dest;
     $BB losetup -d $loop) 2>/dev/null;