shrpx: Log stream id for spdy connection

examples/shrpx_downstream.cc

@@ -363,7 +363,8 @@ int Downstream::push_request_headers()
 
   hdrs += "\r\n";
   if(ENABLE_LOG) {
-    LOG(INFO) << "Downstream request headers\n" << hdrs;
+    LOG(INFO) << "Downstream request headers id="
+              << stream_id_ << "\n" << hdrs;
   }
   bufferevent *bev = dconn_->get_bev();
   evbuffer *output = bufferevent_get_output(bev);

examples/shrpx_spdy_upstream.cc

@@ -192,7 +192,9 @@ void on_ctrl_recv_callback
       for(size_t i = 0; nv[i]; i += 2) {
         ss << nv[i] << ": " << nv[i+1] << "\n";
       }
-      LOG(INFO) << "Upstream spdy request headers:\n" << ss.str();
+      LOG(INFO) << "Upstream spdy request headers id="
+                << downstream->get_stream_id()
+                << "\n" << ss.str();
     }
 
     DownstreamConnection *dconn;