[gegl] tests: update reference image for stretch-contrast

[Øyvind Kolås <ok src gnome org>]

commit 4c1cab927e37c0652d8b76bb06207a8fe40cf376
Author: Øyvind Kolås <pippin gimp org>
Date:   Sat Nov 21 04:17:49 2015 +0100

    tests: update reference image for stretch-contrast

 tests/compositions/reference/stretch-contrast.png |  Bin 3358 -> 2921 bytes
 1 files changed, 0 insertions(+), 0 deletions(-)
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diff --git a/tests/compositions/reference/stretch-contrast.png 
b/tests/compositions/reference/stretch-contrast.png
index 0bb55c0..29cd231 100644
Binary files a/tests/compositions/reference/stretch-contrast.png and 
b/tests/compositions/reference/stretch-contrast.png differ