Fix file error

Author: agiuliano

cookbook/doctrine/file_uploads.rst

@@ -120,9 +120,10 @@ look like this::
 Next, create this property on your ``Document`` class and add some validation
 rules::
 
-use Symfony\Component\HttpFoundation\File\UploadedFile;
+    use Symfony\Component\HttpFoundation\File\UploadedFile;
 
     // ...
+
     class Document
     {
         /**
@@ -322,7 +323,7 @@ object, which is what's returned after a ``file`` field is submitted::
         $this->path = $this->getFile()->getClientOriginalName();
 
         // clean up the file property as you won't need it anymore
-        $this->setFile(null);
+        $this->file = null;
     }
 
 Using Lifecycle Callbacks
@@ -417,7 +418,7 @@ Next, refactor the ``Document`` class to take advantage of these callbacks::
                 // clear the temp image path
                 $this->temp = null;
             }
-            $this->setFile(null);
+            $this->file = null;
         }
 
         /**