[gtranslator] app: Correct pointer type to get private

[Daniel Garcia Moreno <danigm src gnome org>]

commit 78cb783f1e90daa26eaa7429d0093229a39db2da
Author: Daniel García Moreno <danigm wadobo com>
Date:   Sun Sep 16 10:31:14 2018 +0200

    app: Correct pointer type to get private

 src/gtr-application.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/src/gtr-application.c b/src/gtr-application.c
index f126940e..534ec413 100644
--- a/src/gtr-application.c
+++ b/src/gtr-application.c
@@ -424,7 +424,8 @@ static void
 gtr_application_startup (GApplication *application)
 {
   GtkBuilder *builder;
-  GtrApplicationPrivate *priv = gtr_application_get_instance_private (application);
+  GtrApplication *app = GTR_APPLICATION (application);
+  GtrApplicationPrivate *priv = gtr_application_get_instance_private (app);
 
   G_APPLICATION_CLASS (gtr_application_parent_class)->startup (application);