- Make resume_bdev global to file, so we don't have to pass it around (we 
  always use the same one, so it shouldn't make a difference).

- Allocate cur in read_suspend_image(), since it's the only function that
  uses it. 

- Check all errors and make sure we free cur if any happen.

- Make sure to return errors from the functions called, not our own. 

- Free the pagedir if we hit an error after we allocate it.