[gimp] Mark user-visible messages for translation

[Alexandre Prokoudine <aprokoudine src gnome org>]

commit fbf0d33323ccffe3100d60dbab8b2a57ad5aedcf
Author: Alexandre Prokoudine <alexandre prokoudine gmail com>
Date:   Thu Sep 28 03:59:44 2017 +0300

    Mark user-visible messages for translation

 plug-ins/metadata/metadata-editor.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/plug-ins/metadata/metadata-editor.c b/plug-ins/metadata/metadata-editor.c
index 3629a63..a3f1e00 100644
--- a/plug-ins/metadata/metadata-editor.c
+++ b/plug-ins/metadata/metadata-editor.c
@@ -5612,7 +5612,7 @@ import_dialog_metadata (metadata_editor *args)
   GtkWidget *file_dialog;
   gchar     *filename;
 
-  file_dialog = gtk_file_chooser_dialog_new ("Import Metadata File",
+  file_dialog = gtk_file_chooser_dialog_new (_("Import Metadata File"),
                                              NULL,
                                              GTK_FILE_CHOOSER_ACTION_OPEN,
                                              _("_Cancel"), GTK_RESPONSE_CANCEL,
@@ -5647,7 +5647,7 @@ export_dialog_metadata (metadata_editor *args)
   GtkWidget *file_dialog;
   gchar     *filename;
 
-  file_dialog = gtk_file_chooser_dialog_new ("Export Metadata File",
+  file_dialog = gtk_file_chooser_dialog_new (_("Export Metadata File"),
                                              NULL,
                                              GTK_FILE_CHOOSER_ACTION_SAVE,
                                              _("_Cancel"), GTK_RESPONSE_CANCEL,