The old_password_client_plugin isn't listed in mysql_client_builtins.

Connection to servers using the old password scheme fails with " Plugin mysql_old_password could not be loaded:" (provided that CONC-32 has been fixed). This seems to be due to libmysql/my_auth.c not listing old_password_client_plugin in the mysql_client_builtins array:

$ sed -n -e '46,56p' libmysql/my_auth.c
old_password_auth_client
};

struct st_mysql_client_plugin *mysql_client_builtins[]=
{
(struct st_mysql_client_plugin *)&native_password_client_plugin,
0
};

/* this is a "superset" of MYSQL_PLUGIN_VIO, in C++ I use inheritance */
typedef struct {