• Fixed handing of Linux devices that have multiple slaves. This affects
  the smart/list/devices/down commands [Valentin Hilbig].
• The 'list' command in verbose mode prints the full nanosecond
  timestamp precision.
• After writing content files also sync their directory.
• Fix a invalid time computation that could result in future scrub dates.
  Such dates are fixed automatically at the next scrub or sync.