[gegl] tests: update contrast-curve test result

[Øyvind Kolås <ok src gnome org>]

commit 5f949cca6c1b70213a9daa9aac78cfcfe7a0ffc6
Author: Øyvind Kolås <pippin gimp org>
Date:   Fri Sep 29 00:38:57 2017 +0200

    tests: update contrast-curve test result
    
    The result of this test changed with babl commit
    
      d730e96b6ed75275911de8b02fc9e6d725198e13
      babl: add matrix re-equalization
    
    Our new RGB constants give a neutral gray axis and should thus be and
    improvement.

 tests/compositions/reference/contrast-curve.png |  Bin 265335 -> 265342 bytes
 1 files changed, 0 insertions(+), 0 deletions(-)
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diff --git a/tests/compositions/reference/contrast-curve.png b/tests/compositions/reference/contrast-curve.png
index c23a6bc..267a785 100644
Binary files a/tests/compositions/reference/contrast-curve.png and 
b/tests/compositions/reference/contrast-curve.png differ