[shotwell] Add missing About action

[Jens Georg <jensgeorg src gnome org>]

commit 38347d6e03930e479c1fdcceb63291694fe383e5
Author: Jens Georg <mail jensge org>
Date:   Wed Nov 23 18:53:26 2016 +0100

    Add missing About action
    
    Signed-off-by: Jens Georg <mail jensge org>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=774901

 src/AppWindow.vala |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/AppWindow.vala b/src/AppWindow.vala
index 41751e8..4d9bb27 100644
--- a/src/AppWindow.vala
+++ b/src/AppWindow.vala
@@ -447,6 +447,7 @@ public abstract class AppWindow : PageWindow {
     }
 
     private const GLib.ActionEntry[] common_actions = {
+        { "CommonAbout", on_about },
         { "CommonQuit", on_quit },
         { "CommonFullscreen", on_fullscreen },
         { "CommonHelpContents", on_help_contents },