Merge quant.(none):/ext/mysql/bk/mysql-5.1-bug21123

into  quant.(none):/ext/mysql/bkroot/mysql-5.1-new-rpl-a

sql/slave.cc

@@ -2015,13 +2015,14 @@ pthread_handler_t handle_slave_io(void *arg)
   {
     /*
       Register ourselves with the master.
-      If fails, this is not fatal - we just print the error message and go
-      on with life.
     */
     thd->proc_info = "Registering slave on master";
-    if (register_slave_on_master(mysql) ||  update_slave_list(mysql, mi))
+    if (register_slave_on_master(mysql))
+    {
+      sql_print_error("Slave I/O thread couldn't register on master");
       goto err;
     }
+  }
 
   DBUG_PRINT("info",("Starting reading binary log from master"));
   while (!io_slave_killed(thd,mi))