- Detect device mounted for DVD and suppress be sure to

  mount message after label.
- Set Cleaning tape status to "Cleaning" and force no
  MediaType.
- Get DVD writing working with new standard Bacula open()
  code.
- Rename get_filename() to make more sense.
- Detect "is already mounted on" on mount command so to avoid
  error if device is already mounted.
- Eliminated guess_name() code. It may be necessary to
  add it back later.
- Eliminate seg fault from printing invalid results.
- Make dvd_write_part() bool.