[gegl] Issue #108 - RGB Noise doesn't produce output on white layer

[Ell <ell src gnome org>]

commit 6a2325d1bdad41f97da8b3fbbee307605ef21586
Author: Ell <ell_se yahoo com>
Date:   Thu Nov 1 02:06:17 2018 -0400

    Issue #108 - RGB Noise doesn't produce output on white layer
    
    In gegl:noise-rgb, add noise even when the amount is negative.
    
    This fixes a regression, introduced by commit
    8681bf105e683aa41bbf132f3ac0989f1d5a6a22.

 operations/common/noise-rgb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/operations/common/noise-rgb.c b/operations/common/noise-rgb.c
index d6ea39085..9708156dc 100644
--- a/operations/common/noise-rgb.c
+++ b/operations/common/noise-rgb.c
@@ -163,7 +163,7 @@ process (GeglOperation       *operation,
       if (b == 0 || o->independent || b == 3 )
          noise_coeff = noise[b] * noise_fun (o->rand, x, y, &n) * 0.5;
 
-      if (noise_coeff > 0.0)
+      if (noise_coeff != 0.0)
       {
         if (o->correlated)
         {