[gnome-photos/gnome-3-22] Update to latest libgd

[Debarshi Ray <debarshir src gnome org>]

commit 6efec78008c8298d16be2786db8f64de4d563e50
Author: Debarshi Ray <debarshir gnome org>
Date:   Sat Nov 26 18:48:59 2016 +0100

    Update to latest libgd
    
    Ignore the generated resource files for GdTaggedEntry.

 libgd |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/libgd b/libgd
index eb1e24e..8ad0d8c 160000
--- a/libgd
+++ b/libgd
@@ -1 +1 @@
-Subproject commit eb1e24e96ecbd58c85090fff61ab6d5418880946
+Subproject commit 8ad0d8c63ac7be212c54be4e7fb802c239132239