[gimp] app: fix grain_extract behavior

[Øyvind Kolås <ok src gnome org>]

commit 579676cfe42cd7c417cb1a46c3073af8fa3bd7ee
Author: Øyvind Kolås <pippin gimp org>
Date:   Tue Jan 24 19:19:16 2017 +0100

    app: fix grain_extract behavior
    
    The blending function of grain merge was being used instead of grain extract.

 .../layer-modes/gimpoperationlayermode.c           |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/app/operations/layer-modes/gimpoperationlayermode.c 
b/app/operations/layer-modes/gimpoperationlayermode.c
index 1ae0934..a1a3513 100644
--- a/app/operations/layer-modes/gimpoperationlayermode.c
+++ b/app/operations/layer-modes/gimpoperationlayermode.c
@@ -1583,7 +1583,7 @@ static inline GimpBlendFunc gimp_layer_mode_get_blend_fun (GimpLayerMode mode)
     case GIMP_LAYER_MODE_GRAIN_MERGE_LINEAR:
     case GIMP_LAYER_MODE_GRAIN_MERGE:    return blendfun_grain_merge;
     case GIMP_LAYER_MODE_GRAIN_EXTRACT_LINEAR:
-    case GIMP_LAYER_MODE_GRAIN_EXTRACT:  return blendfun_grain_merge;
+    case GIMP_LAYER_MODE_GRAIN_EXTRACT:  return blendfun_grain_extract;
     case GIMP_LAYER_MODE_DODGE_LINEAR: 
     case GIMP_LAYER_MODE_DODGE:          return blendfun_dodge;
     case GIMP_LAYER_MODE_OVERLAY_LINEAR:
@@ -1647,4 +1647,5 @@ static inline GimpBlendFunc gimp_layer_mode_get_blend_fun (GimpLayerMode mode)
     case GIMP_LAYER_MODE_ANTI_ERASE:
       return (void*)dummy_fun;
   }
+  return (void*)dummy_fun;
 }