[gnome-todo] manager: Use #pragma once

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit de0940f342156a664a108dabbeb92a4d2cba2671
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Mon Sep 10 21:54:52 2018 -0300

    manager: Use #pragma once

 src/engine/gtd-manager-protected.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/src/engine/gtd-manager-protected.h b/src/engine/gtd-manager-protected.h
index 546a6da..d1ee773 100644
--- a/src/engine/gtd-manager-protected.h
+++ b/src/engine/gtd-manager-protected.h
@@ -16,8 +16,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef GTD_MANAGER_PROTECTED_H
-#define GTD_MANAGER_PROTECTED_H
+#pragma once
 
 #include "gtd-types.h"
 
@@ -29,4 +28,4 @@ GtdPluginManager*    gtd_manager_get_plugin_manager              (GtdManager
 
 G_END_DECLS
 
-#endif /* GTD_MANAGER_PROTECTED_H */
+G_END_DECLS