Merge pull request #3 from matthewoliver/swift-new

Add a validation step before any rings are touched
Fix typos on build_ring(s) def

* Fix build_rings to be "build_ring".
* Fix syntax around print statement
* Adjust part_power message to let you know what the part_power is in
  the ring, and what it is in the inventory so it can be adjusted.
Make ring_builder understand the conf_d parameter

This change allows the ring_builder to follow the conf_d parameter
and load in conf.d files. This will allow us to point to the main
rpc_user_config.yml and build swift rings no matter where a user/op
may add swift definitions.

It loads in the conf_d parameter, and if it exists, it will search for
the folder:

  - If it looks like a full path (starts with '/') it will attempt to
    use it.

  - If it looks like a relative path then:
        * it will first look for it  being relative to the current
          working directory.

        * then look for the conf_d directory relative to the config file
          passed in.