[simple-scan/gnome-3-30] Do not override existing file if user does not want to do it.

[Robert Ancell <rancell src gnome org>]

commit 973d2444047155fb3e53a783d93fa95cc3fa16dd
Author: Victor Mireyev <victor opennodecloud com>
Date:   Mon Feb 18 16:51:09 2019 +0300

    Do not override existing file if user does not want to do it.

 src/app-window.vala | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/src/app-window.vala b/src/app-window.vala
index 67c882c..553369e 100644
--- a/src/app-window.vala
+++ b/src/app-window.vala
@@ -450,6 +450,8 @@ public class AppWindow : Gtk.ApplicationWindow
 
             if (check_overwrite (save_dialog, files))
                 break;
+            else
+                uri = null;
         }
 
         settings.set_string ("save-directory", save_dialog.get_current_folder ());