Use the OkHttp driver in Marconi to support PATCH methods

Use the OkHttp driver to support PATCH methods.
Also upgraded to OkHttp 1.3.0 (the version is now defined in `jclouds-project`.

Run all live tests against Rackspace cloud queues and all succeeded, including the `updateClaim` one:

    Tests run: 32, Failures: 0, Errors: 0, Skipped: 0

/cc @everett-toews @zack-shoylev