[gegl] over: add reference-hash

[Øyvind Kolås <ok src gnome org>]

commit 627030294bc402c2d1ac29f18d314c17183c0c4a
Author: Øyvind Kolås <pippin gimp org>
Date:   Thu Mar 16 19:05:59 2017 +0100

    over: add reference-hash

 operations/common/over.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/over.c b/operations/common/over.c
index d674b88..dad8d9f 100644
--- a/operations/common/over.c
+++ b/operations/common/over.c
@@ -182,6 +182,7 @@ gegl_op_class_init (GeglOpClass *klass)
     "title",       _("Normal compositing"),
     "compat-name", "gegl:over",
     "categories" , "compositors:porter-duff",
+    "reference-hash", "4927f3cc0372acb702695c7dc4b90785",
     "description",
           _("Porter Duff operation over (also known as normal mode, and src-over) (d = cA + cB * (1 - aA))"),
     "cl-source"  , svg_src_over_cl_source,