[babl] tests: use a epsilon instead of == for float compare

[Øyvind Kolås <ok src gnome org>]

commit 54cc1d1b1e1d65469cb51d97f340d29f579b7d92
Author: Øyvind Kolås <pippin gimp org>
Date:   Mon Sep 25 20:33:17 2017 +0200

    tests: use a epsilon instead of == for float compare

 tests/grayscale_to_rgb.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/tests/grayscale_to_rgb.c b/tests/grayscale_to_rgb.c
index 7da0c86..b239e23 100644
--- a/tests/grayscale_to_rgb.c
+++ b/tests/grayscale_to_rgb.c
@@ -59,7 +59,7 @@ test (void)
 
   for (i = 0; i < PIXELS * 3; i++)
     {
-      if (rgb_buf[i] != rgb_buf_ref[i])
+      if (fabs (rgb_buf[i] - rgb_buf_ref[i]) > 0.0000001)
         {
           babl_log ("index %i is problematic : %f instead of %f",
                     i, rgb_buf[i], rgb_buf_ref[i]);