can't make any permissions change in 2.2.4

[Kai Wang]

I used to able to add/drop users and modify permissions in 2.1.1. After
upgrading to 2.2.4, I can't modify any of those. "List all permissions"
returns me all the permissions I setup before the upgrade. But I can't add
new permission or add new users in cqlsh. "create user" and "grant" didn't
report any errors.