Remove public interface that was only needed for testing

Signed-off-by: Morris Jobke <hey@morrisjobke.de>

lib/public/AppFramework/Http/FileDisplayResponse.php

@@ -66,13 +66,4 @@ class FileDisplayResponse extends Response implements ICallbackResponse {
 			$output->setOutput($this->file->getContent());
 		}
 	}
-
-	/**
-	 * Returns the response file.
-	 *
-	 * @return \OCP\Files\File|\OCP\Files\SimpleFS\ISimpleFile
-	 */
-	public function getFile() {
-		return $this->file;
-	}
 }

tests/Core/Controller/GuestAvatarControllerTest.php

@@ -85,6 +85,5 @@ class GuestAvatarControllerTest extends \Test\TestCase {
 
 		$this->assertGreaterThanOrEqual(201, $response->getStatus());
 		$this->assertInstanceOf(FileDisplayResponse::class, $response);
-		$this->assertSame($this->file, $response->getFile());
 	}
 }