[debugger] use newly added eval argument for REPLServer

lib/_debugger.js

@@ -640,8 +640,8 @@ function Interface() {
     self.killChild();
   });
 
-  this.repl = new repl.REPLServer('debug> ');
-  this.repl.eval = this.controlEval.bind(this);
+  this.repl = new repl.REPLServer('debug> ', null,
+                                  this.controlEval.bind(this));
 
   // Lift all instance methods to repl context
   var proto = Interface.prototype,