[ocrfeeder] Fix error on creating warning message dialog for error scanning page

[Joaquim Rocha <jrocha src gnome org>]

commit 8a3e6696724474ebc175a1b02ba1f96f436a4abb
Author: scx <scx mail gmail com>
Date:   Mon Jan 6 20:26:31 2020 +0100

    Fix error on creating warning message dialog for error scanning page
    
    SimpleDialog constructor requires to provide the parent window.

 src/ocrfeeder/studio/studioBuilder.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/ocrfeeder/studio/studioBuilder.py b/src/ocrfeeder/studio/studioBuilder.py
index f713c7c..7a2ccdc 100644
--- a/src/ocrfeeder/studio/studioBuilder.py
+++ b/src/ocrfeeder/studio/studioBuilder.py
@@ -231,7 +231,7 @@ class Studio:
             self.__addImagesToReviewer([image_path])
             Gdk.threads_leave()
         else:
-            error = widgetPresenter.SimpleDialog(\
+            error = widgetPresenter.SimpleDialog(self.main_window,
                                              _("Error scanning page"),
                                              _("Error"),
                                              'warning')