Return locked out message from sessions controller when resource is locked

[TylerRockwell]

Why?

Currently, when a user account is locked, devise token auth returns an error stating:

A confirmation email was sent to your account at user@example.com.
You must follow the instructions in the email before your account can be activated

This message can be misleading, especially when the :confirmable module is not in use.

What Changed?

When an account is locked devise token auth now returns this message:

Your account has been locked due to an excessive number of unsuccessful sign in attempts.

[zachfeldman]

Makes sense to me! If another contributor approves, I'll merge.

[TylerRockwell]

Excellent. Thanks for the quick response and merge @zachfeldman and @MaicolBen .

[zachfeldman]

Thanks for your contribution!