Fix cpplint errors in p2p/

Bug: webrtc:5273
Change-Id: Ida3c2ca1bbb611026f34d7144db9ec24840bf7fb
Reviewed-on: https://webrtc-review.googlesource.com/26444
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21133}

p2p/base/tcpport.h

@@ -100,7 +100,7 @@ class TCPPort : public Port {
   void OnAddressReady(rtc::AsyncPacketSocket* socket,
                       const rtc::SocketAddress& address);
 
-  // TODO: Is this still needed?
+  // TODO(?): Is this still needed?
   bool incoming_only_;
   bool allow_listen_;
   rtc::AsyncPacketSocket* socket_;