Fix bug in process.mixin where deep copies would not work at all.

Before, doing this:

    var sys = require("sys");

    var obj = {
      one: 1,
      two: 2,
      three: {
        value: 3
      }
    };

    sys.p(process.mixin(true, {}, obj));

Would output this:

    {
     "two": 2,
     "three": {
      "one": 1,
      "two": 2,
      "three": {
       "value": 3
      },
      "value": 3
     },
     "one": 1
    }

When it should have outputed this:

    {
     "one": 1,
     "two": 2,
     "three": {
      "value": 3
     }
    }

src/node.js

@@ -135,18 +135,20 @@ process.mixin = function() {
         var d = Object.getOwnPropertyDescriptor(source, k);
         if (d.get) {
           target.__defineGetter__(k, d.get);
-          if (d.set)
+          if (d.set) {
             target.__defineSetter__(k, d.set);
           }
+        }
         else {
           // Prevent never-ending loop
-          if (target === d.value)
+          if (target === d.value) {
             continue;
+          }
 
           if (deep && d.value && typeof d.value === "object") {
             target[k] = process.mixin(deep,
               // Never move original objects, clone them
-              source || (d.value.length != null ? [] : {})
+              source[k] || (d.value.length != null ? [] : {})
             , d.value);
           }
           else {

test/mjsunit/test-process-mixin.js

@@ -13,7 +13,7 @@ var fakeDomElement = {deep: {nodeType: 4}};
 target = {};
 process.mixin(true, target, fakeDomElement);
 
-assert.notStrictEqual(target.deep, fakeDomElement.deep);
+assert.deepEqual(target.deep, fakeDomElement.deep);
 
 var objectWithUndefinedValue = {foo: undefined};
 target = {};