CubeCamera: Clean up.

src/cameras/CubeCamera.js

@@ -43,7 +43,9 @@ THREE.CubeCamera = function ( near, far, cubeResolution ) {
 	cameraNZ.lookAt( new THREE.Vector3( 0, 0, - 1 ) );
 	this.add( cameraNZ );
 
-	this.renderTarget = new THREE.WebGLRenderTargetCube( cubeResolution, cubeResolution, { format: THREE.RGBFormat, magFilter: THREE.LinearFilter, minFilter: THREE.LinearFilter } );
+	var options = { format: THREE.RGBFormat, magFilter: THREE.LinearFilter, minFilter: THREE.LinearFilter };
+
+	this.renderTarget = new THREE.WebGLRenderTargetCube( cubeResolution, cubeResolution, options );
 
 	this.updateCubeMap = function ( renderer, scene ) {