Line2NodeMaterial: Fix the warn on cache-key, keep it in `set lineColorNode`.

src/materials/nodes/Line2NodeMaterial.js

@@ -538,8 +538,6 @@ class Line2NodeMaterial extends NodeMaterial {
 	 */
 	get lineColorNode() {
 
-		warnOnce( 'Line2NodeMaterial: "lineColorNode" has been deprecated. Use "colorNode" instead.' ); // @deprecated r185
-
 		return this.colorNode;
 
 	}