Remove some unnecessary use statements

Author: Algatux

src/Client.php

@@ -2,11 +2,8 @@
 
 namespace MongoDB;
 
-use MongoDB\Driver\Command;
-use MongoDB\Driver\Cursor;
 use MongoDB\Driver\Manager;
 use MongoDB\Driver\ReadPreference;
-use MongoDB\Driver\WriteConcern;
 use MongoDB\Exception\InvalidArgumentException;
 use MongoDB\Model\DatabaseInfoIterator;
 use MongoDB\Operation\DropDatabase;