[shotwell] Use MessageDialog's printf for strings

[Jens Georg <jensgeorg src gnome org>]

commit 2744ffdc377cb7b5b42d67d3e3c469f8b6cac19a
Author: Jens Georg <mail jensge org>
Date:   Sat Jul 23 08:28:44 2016 +0200

    Use MessageDialog's printf for strings
    
    Fixes issue where mark-up was shown as-is
    
    Signed-off-by: Jens Georg <mail jensge org>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=768360

 src/Dialogs.vala |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/src/Dialogs.vala b/src/Dialogs.vala
index 4f9e7f4..f01e078 100644
--- a/src/Dialogs.vala
+++ b/src/Dialogs.vala
@@ -31,9 +31,10 @@ public bool confirm_delete_saved_search(SavedSearch search) {
 
 public bool confirm_warn_developer_changed(int number) {
     Gtk.MessageDialog dialog = new Gtk.MessageDialog.with_markup(AppWindow.get_instance(),
-        Gtk.DialogFlags.MODAL, Gtk.MessageType.WARNING, Gtk.ButtonsType.NONE, "%s",
-        "<span weight=\"bold\" size=\"larger\">%s</span>".printf(ngettext("Switching developers will undo 
all changes you have made to this photo in Shotwell",
-        "Switching developers will undo all changes you have made to these photos in Shotwell", number)));
+        Gtk.DialogFlags.MODAL, Gtk.MessageType.WARNING, Gtk.ButtonsType.NONE,
+        "<span weight=\"bold\" size=\"larger\">%s</span>",
+        ngettext("Switching developers will undo all changes you have made to this photo in Shotwell",
+        "Switching developers will undo all changes you have made to these photos in Shotwell", number));
 
     dialog.add_buttons(Resources.CANCEL_LABEL, Gtk.ResponseType.CANCEL);
     dialog.add_buttons(_("_Switch Developer"), Gtk.ResponseType.YES);