Change client_flag to unsigned long (16 -> 32 bits) to handle more options.

Don't use new password format if mysql.user has old format
tables_priv was not reset on FLUSH PRIVILEGES if tables_priv was empty
Portability fixes for Windows

mysql-test/r/rpl_loaddata.result

@@ -1,9 +1,9 @@
-slave stop;
+stop slave;
 drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
 reset master;
 reset slave;
 drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
-slave start;
+start slave;
 create table t1(a int not null auto_increment, b int, primary key(a) );
 load data infile '../../std_data/rpl_loaddata.dat' into table t1;
 select * from t1;