GLSL files should go into $(LIBO_ETC_FOLDER)/opengl

(And not $(LIBO_BIN_FOLDER)/opengl. Note that on Linux and Windows,
LIBO_ETC_FOLDER and LIBO_BIN_FOLDER are the same, "program".)

That's where getShaderFolder() in vcl/source/opengl/OpenGLHelper.cxx
looks for them. Also, as they are data and not executable code, to
conform to strict OS X code signing and sandboxing requirements, they
definitely should not be in $(LIBO_BIN_FOLDER)

Change-Id: I902e08f7a1f142697df827d50e0bda74be918eb4