DB comment size has been increased since MySQL-5.5.3 so increase it
Remove FK check off of MySQL when all drop DDLs are off.
Merge pull request #1 from jflute/mysql_ddl_fkconstraint_problem

Remove FK check off of MySQL when all drop DDLs are off.
Merge pull request #1 from jflute/master

DB comment size has been increased since MySQL-5.5.3 so increase it