Fixing type hint in remote manager.  IoC could not resolve without it.

Found this when pulling it in manually on a 4.3 install.  If I am correct that it is being removed from 4.3 and this is how we add it back, this one thing causes the following error.

```
exception 'Illuminate\Container\BindingResolutionException' with message 'Unresolvable dependency resolving [Parameter #0 [ <required> $app ]] in class Illuminate\Remote\RemoteManager' in /home/stygian/dev/base43/vendor/laravel/framework/src/Illuminate/Container/Container.php:677
```
Please use the contract here. `Illuminate\Contracts\Foundation\Application`