Comment 2 for bug 1575688

from what I've seen - if you had the database already created when utf8mb4 was still in the configs, the database got created with those settings and changing them in the config files makes no diff on future calls for table create and index out of range.

drop the database - there is nothing in it yet anyway - and recreate it after config file changes are in and mysqld restarted, exactly the same way you just created them in the first place. after this the table create will fly right through.