s3:auth: make use of make_{server,session}_info_anonymous()

s3:auth: make use of make_{server,session}_info_anonymous()

It's important to have them separated from make_{server,session}_info_guest(),
because there's a fundamental difference between anonymous (the client requested
no authentication) and guest (the server lies about the authentication failure).

When it's really an anonymous connection, we should reflect that in the
resulting session info.

This should fix a problem where Windows 10 tries to join
a Samba hosted NT4 domain and has SMB2/3 enabled.

We no longer return SMB_SETUP_GUEST or SMB2_SESSION_FLAG_IS_GUEST
for true anonymous connections.

The commit message from a few commit before shows the resulting
auth_session_info change.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13328

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
Autobuild-User(master): Ralph Böhme <slow@samba.org>
Autobuild-Date(master): Fri Mar 16 03:03:31 CET 2018 on sn-devel-144