protocol: new SASL layers

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

I believe this text should be deleted.
>   If a SASL transfer encryption or integrity mechanism has been negotiated,
>   that mechanism does not support the changing of credentials from one
>   identity to another, then the client MUST instead establish a new
>   connection.

Each SASL negotiation is, generally, independent of other SASL
negotiations.  If there were dependencies between multiple
negotiations of a particular mechanism, the mechanism technical
specification should detail how applications are to deal with
them.  LDAP should not require any special handling.  And if
an LDAP client had used such a mechanism, it would have the
option of using another mechanism.

Comments?

Kurt