Remove hidden service version 0 directory code

From the ChangeLog:

Changes in version 0.2.2.1-alpha - 2009-08-26
    - Hidden services no longer publish version 0 descriptors, and clients
      do not request or use version 0 descriptors. However, the old hidden
      service authorities still accept and serve version 0 descriptors
      when contacted by older hidden services/clients.

Nick, would you accept a patch that removes version 0 hidden service code? Or would you prefer writing that patch yourself and me reviewing it?