Changed C++ style comment to C style for 'sql/net_serv.cc' which will be symlinked

to 'libmysql/net.c'.

sql/net_serv.cc

@@ -227,7 +227,7 @@ int
 my_net_write(NET *net,const char *packet,ulong len)
 {
   uchar buff[NET_HEADER_SIZE];
-  if (unlikely(!net->vio)) // nowhere to write
+  if (unlikely(!net->vio)) /* nowhere to write */
     return 0;
   /*
     Big packets are handled by splitting them in packets of MAX_PACKET_LENGTH