[gegl] mix: add reference-hash

[Øyvind Kolås <ok src gnome org>]

commit ce0990509b09ac26a39817353d7f5ec7aae53d54
Author: Øyvind Kolås <pippin gimp org>
Date:   Sat Nov 11 21:51:01 2017 +0100

    mix: add reference-hash

 operations/common/mix.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/mix.c b/operations/common/mix.c
index 34169ea..94b8248 100644
--- a/operations/common/mix.c
+++ b/operations/common/mix.c
@@ -89,6 +89,7 @@ gegl_op_class_init (GeglOpClass *klass)
   gegl_operation_class_set_keys (operation_class,
     "name"       , "gegl:mix",
     "title",       _("Mix"),
+    "reference-hash", "20c678baa5b1f5c72692ab9dce6a5951",
     "description",
           _("do a lerp, linear interpolation (lerp) between input and aux"),
     NULL);