Passing provider to lookupAdapter in session#close, and passing options to adapter

This fixes session#close so that custom adapters will no longer cause a "not implemented" exception.
heh, quite cryptic but this is correct. I suggest changing the assertion to only check about the arguments instead of looking at the state of the promise:

```
session.close('dummy-success', opts).finally(function(){
  equal(optionsCloseCalledWith, opts, 'options should be passed through to adapter');
});
```

By using finally you disregard the success/failure state of the promise, and just know that is has settled.