LDAP service name

[Chris Newman <Chris.Newman@innosoft.com>]

Profiling requirement 1 of the SASL specification (RFC 2222, section 4)
does not seem to be met by the current LDAP SASL profile.

In particular, you need to specify a service name for use with ldap and
register it with IANA at the GSSAPI service registry:

 <http://www.isi.edu/in-notes/iana/assignments/gssapi-service-names>

The concept of a "service name" is used by GSSAPI, SASL, Kerberos and
SCRAM-MD5.  When different services have different security risks, it's
important that the server-side credentials are managed on a per-service
basis.  In addition, users occasionally want different passwords for
different services and the service name creates the distinction.

You might also want to use "host" as a fallback service name if the ldap
service name isn't available.  This what ftp security does (RFC 2228,
appendix I).

		- Chris