[gnome-photos] Update to latest libgd

[Debarshi Ray <debarshir src gnome org>]

commit c219a2bc69a8d04f6f22604983ce9ea3569f470c
Author: Debarshi Ray <debarshir gnome org>
Date:   Fri Feb 3 11:27:58 2017 +0100

    Update to latest libgd
    
    GdMainBox now adds a frame around the view.

 libgd |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/libgd b/libgd
index f7424f6..7ead068 160000
--- a/libgd
+++ b/libgd
@@ -1 +1 @@
-Subproject commit f7424f67689d47c332137b9305ff850be2340dbb
+Subproject commit 7ead068e487ee2aee2cb1967be6bf9b0497f610a