[gnome-themes-standard] build: add some missing assets to EXTRA_DIST

[Cosimo Cecchi <cosimoc src gnome org>]

commit 6c374d25dce5722dbbb7e26d20b98da55d9170fa
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Wed Feb 13 08:20:31 2013 -0500

    build: add some missing assets to EXTRA_DIST

 themes/Adwaita/gtk-2.0/Makefile.am |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/themes/Adwaita/gtk-2.0/Makefile.am b/themes/Adwaita/gtk-2.0/Makefile.am
index 0872a60..91f63ed 100644
--- a/themes/Adwaita/gtk-2.0/Makefile.am
+++ b/themes/Adwaita/gtk-2.0/Makefile.am
@@ -111,6 +111,8 @@ asset_data = \
         Scrollbars/trough-scrollbar-horiz.png \
 	Scrollbars/trough-scrollbar-vert.png \
 	Shadows/frame.png \
+	Shadows/frame-gap-start.png \
+	Shadows/frame-gap-end.png \
 	Spin/down-background.png \
 	Spin/up-background.png \
 	Spin/down-background-disable.png \