MDEV-22483 mysql_upgrade does not use current user as default for connecting to server

correct the help text

client/mysql_upgrade.c

@@ -153,7 +153,7 @@ static struct my_option my_long_options[]=
    &opt_systables_only, &opt_systables_only, 0,
    GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
 #define USER_OPT (array_elements(my_long_options) - 6)
-  {"user", 'u', "User for login if not current user.", &opt_user,
+  {"user", 'u', "User for login.", &opt_user,
    &opt_user, 0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
   {"verbose", 'v', "Display more output about the process; Using it twice will print connection argument; Using it 3 times will print out all CHECK, RENAME and ALTER TABLE during the check phase.",
    &opt_not_used, &opt_not_used, 0, GET_BOOL, NO_ARG, 1, 0, 0, 0, 0, 0},