Remove needless intermediary

Author: fatso83

lib/sinon/stub.js

@@ -94,14 +94,12 @@ function stub(object, property) {
     var func = typeof actualDescriptor.value === "function" ? actualDescriptor.value : null;
     var s = createStub(func);
 
-    var propIsOwn = Boolean(actualDescriptor.isOwn);
-
     extend.nonEnum(s, {
         rootObj: object,
         propName: property,
-        shadowsPropOnPrototype: !propIsOwn,
+        shadowsPropOnPrototype: !actualDescriptor.isOwn,
         restore: function restore() {
-            if (actualDescriptor !== undefined && propIsOwn) {
+            if (actualDescriptor !== undefined && actualDescriptor.isOwn) {
                 Object.defineProperty(object, property, actualDescriptor);
                 return;
             }

lib/sinon/util/core/get-property-descriptor.js

@@ -3,7 +3,7 @@
 module.exports = function getPropertyDescriptor(object, property) {
     var proto = object;
     var descriptor;
-    var isOwn = object && Object.getOwnPropertyDescriptor(object, property);
+    var isOwn = Boolean(object && Object.getOwnPropertyDescriptor(object, property));
 
     while (proto && !(descriptor = Object.getOwnPropertyDescriptor(proto, property))) {
         proto = Object.getPrototypeOf(proto);