repl: don't write a newline on the readline 'end' event

In the case of the input stream *actually* having been closed, then we
can't write to a closed socket.

Fixes test/simple/test-repl.js

lib/repl.js

@@ -176,7 +176,6 @@ function REPLServer(prompt, stream, eval, useGlobal, ignoreUndefined) {
   rli.setPrompt(self.prompt);
 
   rli.on('end', function() {
-    self.rli.output.write('\n');
     self.emit('exit');
   });