- Revert small iso fix, it resulted in incorrect checksums
      Resolves: rhbz#2277398
    
    The small iso checksum fix included in version 1.2.4 resulted in it
    writing truncated checksums. These checksums passed, but only when
    checked by v1.2.4 and they don't cover the last part of the iso.
    This reverts that change, and is compatible with previous versions.