If no options are given to child_process.spawn, env should default to process.env

Regression.

lib/child_process.js

@@ -164,10 +164,11 @@ ChildProcess.prototype.kill = function (sig) {
 
 ChildProcess.prototype.spawn = function (path, args, options, customFds) {
   args = args || [];
-  options = options || {};
 
   var cwd, env;
-  if (options.cwd === undefined && options.env === undefined && options.customFds === undefined) {
+  if (!options || options.cwd === undefined &&
+      options.env === undefined &&
+      options.customFds === undefined) {
     // Deprecated API: (path, args, options, env, customFds)
     cwd = "";
     env = options || process.env;