Docker: don't send wrong parameters to client.start()

As part of being updated for the 1.10 API, a couple of parameters were added to the kwargs that are passed to the docker.client.start() command that it doesn't accept. This caused the module to error out if it tried to start any Docker containers. This removes those parameters so the module works again.

For reference, here is the method signature for `docker.client.start`:
```
    def start(self, container, binds=None, port_bindings=None, lxc_conf=None,
              publish_all_ports=False, links=None, privileged=False):
```
Note that neither `dns` nor `volumes_from` are kwargs.