Cloned from launchpad blueprint https://blueprints.launchpad.net/keystone/+spec/user-password-expiration.

Description:

User password with limited life span is a requirement in some enterprise environments. This proposal addresses the demand by introducing:
* specific exception and HTTP response ('401 Password expired') in Keystone API;
* storing password TTL param in database and passing 'expired password'-specific exception to the core from SQL identity backend;
* handling 'password expired' error and passing 'expired password'-specific exception to the core from LDAP identity backend.

Specification URL (additional information):

None