BGE bugfix for [#34505] Vertex Colors not working in the BGE (for custom GLSL shaders) when multitexture and no material

Bug introduced on rev.36723

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55487 954f8c5b-7b00-dc11-b283-0030488c597c