* Translate bandwidth spec "~" to 10Kbps, and complain if any other value
  is used on a lan with blockstores.

* Allow blockstores to be fixed to nodes.  Shunt through cases where the
  node a blockstore is fixed to isn't a blockstore pseudo-VM via a
  features / desires hack.  We do this to avoid having a more heavyweight
  blockstore pseudo-VM representation show up when users just want more
  local disk space setup on their nodes.