Fix xcode build warning in shell.cc

(out of order initialization).

BUG=
TEST=

Review URL: http://codereview.chromium.org/6772021

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7419 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

samples/shell.cc

@@ -157,7 +157,7 @@ class SourceGroup {
   class IsolateThread : public v8::internal::Thread {
    public:
     explicit IsolateThread(SourceGroup* group)
-        : group_(group), v8::internal::Thread(NULL, GetThreadOptions()) {}
+        : v8::internal::Thread(NULL, GetThreadOptions()), group_(group) {}
 
     virtual void Run() {
       group_->ExecuteInThread();