[epiphany/gnome-3-22] Update libgd

[Michael Catanzaro <mcatanzaro src gnome org>]

commit e87172e34653e648e50b4d37666dbe79c9133e47
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Sun Aug 21 16:01:29 2016 -0500

    Update libgd
    
    This stops libgd from modifying itself (overwriting its own .gitignore)
    on the first invocation of make.

 libgd |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/libgd b/libgd
index 56a19ad..1f2e074 160000
--- a/libgd
+++ b/libgd
@@ -1 +1 @@
-Subproject commit 56a19ad9b056332ef07e508f1bdb6f03c6cb2590
+Subproject commit 1f2e07409cf085b74370f8a985de849d0f6d4b57