Paginators should be built from Contracts

Follow up to laravel#19328, paginators should not only be built of the container, they should use the interface. This is more correct and gives developers more flexibility in their implementation.

Author: grashoper20

src/Illuminate/Database/Concerns/BuildsQueries.php

@@ -3,8 +3,8 @@
 namespace Illuminate\Database\Concerns;
 
 use Illuminate\Container\Container;
-use Illuminate\Pagination\Paginator;
-use Illuminate\Pagination\LengthAwarePaginator;
+use Illuminate\Contracts\Pagination\Paginator;
+use Illuminate\Contracts\Pagination\LengthAwarePaginator;
 
 trait BuildsQueries
 {