BugTrack/2469 OpenLDAP SHA-2 Support on password (patched by henoheno)

BugTrack/2469 OpenLDAP SHA-2 Support on password (patched by henoheno)

Supported SHA-2 password schemes:
* SHA256, SHA384, SHA512 (LDAP: OpenLDAP compatible)
* SSHA256, SSHA384, SSHA512 (OpenLDAP compatible - Salted version)
* x-php-sha256, x-php-sha384, x-php-512 (Simple hex version)

RFC 6234: US Secure Hash Algorithms (SHA and SHA-based HMAC and HKDF)
https://tools.ietf.org/html/rfc6234

Internet-Draft: Lightweight Directory Access Protocol (LDAP): Hashed Attribute values for 'userPassword' (March 13, 2013)
https://tools.ietf.org/html/draft-stroeder-hashed-userpassword-values-01