[gegl] opacity: add reference hash

[Øyvind Kolås <ok src gnome org>]

commit 343e77e4cb0dad7b10f934c234a44420a93dd31f
Author: Øyvind Kolås <pippin gimp org>
Date:   Sat Mar 11 23:55:58 2017 +0100

    opacity: add reference hash

 operations/common/opacity.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/opacity.c b/operations/common/opacity.c
index 24d4736..ffb4f2d 100644
--- a/operations/common/opacity.c
+++ b/operations/common/opacity.c
@@ -305,6 +305,7 @@ gegl_op_class_init (GeglOpClass *klass)
     "name"       , "gegl:opacity",
     "categories" , "transparency",
     "title",       _("Opacity"),
+    "reference-hash", "b20e8c1d7bb20af95f724191feb10103",
     "description",
           _("Weights the opacity of the input both the value of the aux"
             " input and the global value property."),