[epiphany] download: fix format-security warning

[Michael Catanzaro <mcatanzaro src gnome org>]

commit ef9cf0172ef8928d0951a44a25e0f68ee0e14b8a
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Thu May 2 18:39:06 2019 -0500

    download: fix format-security warning
    
    This only affects 3.33.1, so no stable users were vulnerable.
    
    Fixes #756

 embed/ephy-download.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/embed/ephy-download.c b/embed/ephy-download.c
index b1c66f214..941cdcd44 100644
--- a/embed/ephy-download.c
+++ b/embed/ephy-download.c
@@ -779,7 +779,7 @@ filename_suggested_cb (EphyDownload *download,
                                    "%s",
                                    _("Download requested"));
   gtk_dialog_add_buttons (GTK_DIALOG (dialog), _("_Cancel"), GTK_RESPONSE_CANCEL, _("_Download"), 
GTK_RESPONSE_OK, NULL);
-  gtk_message_dialog_format_secondary_text (GTK_MESSAGE_DIALOG (dialog), suggested_filename);
+  gtk_message_dialog_format_secondary_text (GTK_MESSAGE_DIALOG (dialog), "%s", suggested_filename);
   message_area = gtk_message_dialog_get_message_area (GTK_MESSAGE_DIALOG (dialog));
 
   webkit_download = ephy_download_get_webkit_download (download);