debugger: use v8 api to wait for a connection

Use v8::Debug::EnableAgent(_, _, true) to wait for incoming
debugger-client connection before emitting any break (or other) events.

This commit should fix test/simple/test-debugger-repl faults.

src/node.cc

@@ -2390,15 +2390,9 @@ static void EnableDebug(bool wait_connect) {
   node_isolate->Enter();
 
   // Start the debug thread and it's associated TCP server on port 5858.
-  bool r = v8::Debug::EnableAgent("node " NODE_VERSION, debug_port);
-
-  if (wait_connect) {
-    // Set up an empty handler so v8 will not continue until a debugger
-    // attaches. This is the same behavior as Debug::EnableAgent(_,_,true)
-    // except we don't break at the beginning of the script.
-    // see Debugger::StartAgent in debug.cc of v8/src
-    v8::Debug::SetMessageHandler2(node::DebugBreakMessageHandler);
-  }
+  bool r = v8::Debug::EnableAgent("node " NODE_VERSION,
+                                  debug_port,
+                                  wait_connect);
 
   // Crappy check that everything went well. FIXME
   assert(r);