Bug #28401 mysql_upgrade Failed with STRICT_ALL_TABLES, ANSI_QUOTES and NO_ZERO_DATE

- The SQL commands used by mysql_upgrade are written to be run
    with sql_mode set to '' - thus the scripts should change sql_mode
    for the session to make sure the SQL is legal.

scripts/mysql_system_tables_fix.sql

@@ -9,6 +9,7 @@
 # this sql script.
 # On windows you should do 'mysql --force mysql < mysql_fix_privilege_tables.sql'
 
+set sql_mode='';
 set storage_engine=MyISAM;
 
 ALTER TABLE user add File_priv enum('N','Y') COLLATE utf8_general_ci NOT NULL;