GlusterD2 v4.0dev-5

• Clients can actually get volfiles from GD2.
  • GD2 now has a working SunRPC server that implements the required
    mount and portmap programs and procedures for clients to be able to
    fetch volfiles and mount
  • Portmap doesn't work reliably, but we'll fix it soon. For now, portmap returns ports only if your brick paths are /export/brick{1..4}/data. If not, the client enters into an infinite portmap request loop.
• Multiplexed rest and sunrpc on a single port.
  • One less port to keep open. We could also get gRPC multiplexed on
    this port as well.
• Refactor all the servers and use supervisor-trees
  • All the current servers in GD2 -- gRPC, rest and sunrpc servers --
    have been refactored. They now implement a standard service
    interface that allows them to be managed using supervisor trees.
    More information can be found in the doc/supervisor-trees.md file