Pass clean arguments to deps.clean

In regards to #1550 when you call `mix clean --all` `Mix.Tasks.Clean.run` delegates to `deps.clean` if the `--all` option is passed, however the arguments aren't being passed to `deps.clean` and therefore an error is being raised. `deps.clean` expects either a dependency name or the `--all` flag. This pull request just passes the arguments supplied to `mix clean` onto `mix deps.clean`.