Issue with Grant and hapi session management with multiple apps
I am using grant extensively in my hapi 16 application.
We have an Apps and Integration page and I am using the grant to connect to all the third parties listed there.
I have a critical issue with session management in the grant. 

My callback URL route is 

```
{
  method: ['GET'],
  path: '/integrations/{provider}/callback',
  config: {
    auth: {
      mode: 'required',
      strategy: 'connect'
    },
    handler: connectIntegration
  }
}
```
In my strategy `connect`, I have done 

```
const payload = request.yar.get('grant');
if (!payload.dynamic) {
  throw new Error('Dynamic grant overrides are not set while authenticating the integration');
}
``` 

I use `dynamic` to send important information back to the application like the ID of the third party I am integrating and some other meta info. 

The problem is, it was working fine till I had just one app. The moment I started adding more apps, I started seeing a critical issue.

`dynamic` details of an app I connected earlier were sent while connecting some other app. This is a very critical issue for me which is totally unexpected. Initially, I was having some doubts about my implementation and finally figured out there is something to do with `yar` session management.

On digging deeper from the answer provided by you [here](https://github.com/simov/grant/issues/41) I added 
```
request.yar.reset(); //Clearing of the session once the handshake is done https://github.com/simov/grant/issues/41#issuecomment-163873802
```

After this, I am not able to reproduce the issue I talked about. But I have stumbled upon another problem. Frequently `request.yar.get('grant')` gives me `undefined` in my strategy which stops the callback from executing.

What could be the root cause of this problem? How it can be solved elegantly?

