[geary: 2/3] ConversationListView: Fix shift-to-delete inversion

[Michael Gratton <mjog src gnome org>]

commit 6f44f89b48e5e9f6a6c2c85607792c60ed8023f6
Author: Алексей Шилин <rootlexx mail ru>
Date:   Fri Feb 14 14:17:44 2020 +0300

    ConversationListView: Fix shift-to-delete inversion
    
    The 'Is Shift down' condition was accidentally inverted in commit
    419bc6d051c76c0172d9866958aa978f91dfbaa1, resulting in inconsistency
    between the main toolbar and a conversations list context menu.

 src/client/conversation-list/conversation-list-view.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/client/conversation-list/conversation-list-view.vala 
b/src/client/conversation-list/conversation-list-view.vala
index c5bf6cda..158708ca 100644
--- a/src/client/conversation-list/conversation-list-view.vala
+++ b/src/client/conversation-list/conversation-list-view.vala
@@ -328,7 +328,7 @@ public class ConversationListView : Gtk.TreeView, Geary.BaseInterface {
             GLib.Menu context_menu_model = new GLib.Menu();
             var main = get_toplevel() as Application.MainWindow;
             if (main != null) {
-                if (main.is_shift_down) {
+                if (!main.is_shift_down) {
                     context_menu_model.append(
                         /// Translators: Context menu item
                         ngettext(