mariadb10.1: follow the field type change
mariadb10.1: follow the field type change

Since MariaDB 10.1.36, the following field in FOREIGN_KEY_INFO is
changed.

LEX_STRING *update_method ->
enum_fk_option update_method

mroonga/mroonga,mroonga/mroonga,mroonga/mroonga,mroonga/mroonga