ImfAcesFile.cpp: Fix primary conversion edge case.

This fixes the edge case when the file chromaticities.white != file adopted
neutral.

In such a scenario the adoptedNeutral file attr must be used as the
display white point value passed into RGBtoXYZ() method since
the adaption matrix (Bradform Transform)  is computed using the adopted neutral as its
input white point.

Signed-off-by: Arkell Rasiah <arasiah@pixsystem.com>

OpenEXR/IlmImf/ImfAcesFile.cpp

@@ -395,7 +395,10 @@ AcesInputFile::Data::initColorConversion ()
     V2f fileNeutral = fileChr.white;
 
     if (hasAdoptedNeutral (header))
+    {
 	fileNeutral = adoptedNeutral (header);
+        fileChr.white = fileNeutral; // for RGBtoXYZ() purposes.
+    }
 
     const Chromaticities acesChr = acesChromaticities();