Geometry: Removed unused variable assignation. Fixes #4652.

src/core/Geometry.js

@@ -250,8 +250,6 @@ THREE.Geometry.prototype = {
 
 				for ( f = 0, fl = this.faces.length; f < fl; f ++ ) {
 
-					face = this.faces[ f ];
-
 					faceNormal = new THREE.Vector3();
 					vertexNormals = { a: new THREE.Vector3(), b: new THREE.Vector3(), c: new THREE.Vector3() };