Blender Git Loki

fix T66899: Collada: Shininess/Reflectivity not handled correct

Fixed: The Collada Exporter only supports export of
Lambert Shaders. But Shininess is not supported with
Lambert Shaders. The exporter must not add Shininess
to the Shader data!

Fixed: The Collada Importer adds an illegal value of -1
for reflectivity when this parameters is not defined in
the imported collada data. Now reflectivity is only
set when the import data contains a valid value.

Discarded: The Collada Importer handles shininess in a
dubious way. I have discarded import for now.
This needs to be reworked carefully in 2.81.

Differential Revision: https://developer.blender.org/D5262