change the backlog of listen() from INT_MAX to 65535 due to the reason described…

change the backlog of listen() from INT_MAX to 65535 due to the reason described in https://codereview.appspot.com/7480046/

src/butil/endpoint.cpp

@@ -337,9 +337,10 @@ int tcp_listen(EndPoint point, bool reuse_addr) {
     if (bind(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) != 0) {
         return -1;
     }
-    if (listen(sockfd, INT_MAX) != 0) {
+    if (listen(sockfd, 65535) != 0) {
         //             ^^^ kernel would silently truncate backlog to the value
-        //             defined in /proc/sys/net/core/somaxconn
+        //             defined in /proc/sys/net/core/somaxconn if it is less
+        //             than 65535
         return -1;
     }
     return sockfd.release();