DDC-217 - Fix some missing docblock, unused variable

lib/Doctrine/DBAL/Cache/RowCacheStatement.php

@@ -38,11 +38,6 @@ use Doctrine\DBAL\Connection;
  */
 class RowCacheStatement implements ResultStatement
 {
-    /**
-     * @var \Doctrine\DBAL\Connection
-     */
-    private $conn;
-
     /**
      * @var \Doctrine\Common\Cache\Cache
      */
@@ -111,6 +106,13 @@ class RowCacheStatement implements ResultStatement
         return new self($conn->executeQuery($query, $params, $types), $resultCache, $cacheKey, $lifetime);
     }
 
+    /**
+     *
+     * @param Statement $stmt
+     * @param Cache $resultCache
+     * @param string $cacheKey
+     * @param int $lifetime
+     */
     public function __construct($stmt, $resultCache, $cacheKey, $lifetime = 0)
     {
         $this->statement = $stmt;