No explicit rights provided in the license header

[rahulmohang]

Hi,

The file, https://github.com/openscenegraph/OpenSceneGraph/blob/master/src/osgPlugins/OpenCASCADE/ReaderWriterOpenCASCADE.cpp seems to be an unpublished file without a explicit grant of license to the users. The header file seems to have the correct license though, as seen at https://github.com/openscenegraph/OpenSceneGraph/blob/master/src/osgPlugins/OpenCASCADE/ReaderWriterOpenCASCADE.h.

Can you please check and change the license header if needed?