avoid waiting for dir cache when opening a file

At least this will eliminate the most annoying part of the bug there the
file won't be displayed till the dir cache is completely loaded.

Bug: https://mirror.git.trinitydesktop.org/gitea/TDE/gwenview/issues/17
Signed-off-by: Alexander Golubev <fatzer2@gmail.com>

src/app/mainwindow.cpp

@@ -243,9 +243,9 @@ void MainWindow::openURL(const KURL& url) {
 		mFileViewController->setDirURL(url);
 		mFileViewController->setFocus();
 	} else {
-		mDocument->setURL(url);
 		mFileViewController->setDirURL(url.upURL());
 		mFileViewController->setFileNameToSelect(url.filename());
+		mDocument->setURL(url);
 		mImageViewController->setFocus();
 	}