mysqltest: better error reporting when "shutdown" fails

as a side effect --replace and --error now work for shutdown command

client/mysqltest.cc

@@ -5199,7 +5199,11 @@ void do_shutdown_server(struct st_command *command)
   */
 
   if (timeout && mysql_shutdown(mysql, SHUTDOWN_DEFAULT))
-    die("mysql_shutdown failed");
+  {
+    handle_error(command, mysql_errno(mysql), mysql_error(mysql),
+                 mysql_sqlstate(mysql), &ds_res);
+    DBUG_VOID_RETURN;
+  }
 
   if (!timeout || wait_until_dead(pid, timeout))
   {
@@ -8191,7 +8195,7 @@ static int match_expected_error(struct st_command *command,
 
   SYNOPSIS
   handle_error()
-  q     - query context
+  command   - command
   err_errno - error number
   err_error - error message
   err_sqlstate - sql state