Fix sasl for DIGEST-MD5, PLAIN, and LOGIN mechanisms, which I don't think ever actually worked properly.
Add a sasluser argument if a specific identity is required for the
backend, which if unsupplied, tries to guess if a binddn is present.
(Uwe's previous commit fixed EXTERNAL and GSSAPI, which did work, but
randomly failed due to hash ordering.)
Minor style cleanups, remove duplicate/unecessary logic for anonymous
binds.
Adam Spiers <adam@spiers.net>
Andr Goens <andres.goens@tu-dresden.de>
Alexander Perlis <aperlis@math.lsu.edu>
Davor Ocelic <docelic@crystallabs.io>
Dennis Kaarsemaker <dennis.kaarsemaker@booking.com>
Emile "iMil" Heitor <imil@home.imil.net>
Gertjan Halkes <shelldap@ghalkes.nl>
Giacomo Tenaglia <Giacomo.Tenaglia@cern.ch>
Jonathan Rozes <jonathan@laika.com>
Josef Wells <Josefwells@alumni.utexas.net>
Landry Breuil <landry@openbsd.org>
Lars Täuber <taeuber@bbaw.de>
Michael Granger <ged@faeriemud.org>
Michael Raitza <spacefrogg-devel@meterriblecrew.net>
Mike Hix <m@hix.io>
Peter Marschall <peter@adpm.de>
Rick H. <rickh_shelldap@printstring.com>
Rong-En Fan <rafan@FreeBSD.org>
Salvatore Bonaccorso <carnil@debian.org>
Uwe Kleine-König <uwe@kleine-koenig.org>
Yann Cezard <yann.cezard@univ-pau.fr>