Simpler check for colors in geometry. As suggested by @WestLangley in af042be6ba96a7284e2d3301cc29e45014a4aedd.

src/renderers/WebGLRenderer.js

@@ -3050,7 +3050,7 @@ THREE.WebGLRenderer = function ( parameters ) {
 
 			if ( attributes.color >= 0 ) {
 
-				if ( object.geometry !== undefined && object.geometry.colors.length > 0 || object.geometry.faces.length > 0 ) {
+				if ( object.geometry.colors.length > 0 || object.geometry.faces.length > 0 ) {
 
 					_gl.bindBuffer( _gl.ARRAY_BUFFER, geometryGroup.__webglColorBuffer );
 					enableAttribute( attributes.color );