fix for --harmony_block_scoping

Fixes #1969.

lib/_debugger.js

@@ -438,7 +438,7 @@ Client.prototype.listbreakpoints = function(cb) {
 };
 
 Client.prototype.setBreakpoint = function(req, cb) {
-  var req = {
+  req = {
     command: 'setbreakpoint',
     arguments: req
   };

lib/child_process.js

@@ -303,7 +303,7 @@ exports.execFile = function(file /* args, options, callback */) {
 
 
 var spawn = exports.spawn = function(file, args, options) {
-  var args = args ? args.slice(0) : [];
+  args = args ? args.slice(0) : [];
   args.unshift(file);
 
   var env = (options ? options.env : null) || process.env;

lib/http.js

@@ -608,7 +608,7 @@ OutgoingMessage.prototype.write = function(chunk, encoding) {
   if (this.chunkedEncoding) {
     if (typeof(chunk) === 'string') {
       len = Buffer.byteLength(chunk, encoding);
-      var chunk = len.toString(16) + CRLF + chunk + CRLF;
+      chunk = len.toString(16) + CRLF + chunk + CRLF;
       ret = this._send(chunk, encoding);
     } else {
       // buffer