libcli/smb: fix non mendatory signing against some vendor SMB2 servers.
Windows and Samba always sign the final session setup response
even if signing is not mendatory, but it ensures that the signing
key is correctly in place.
Bug: https://bugzilla.samba.org/show_bug.cgi?id=10146
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Tue Sep 17 09:40:10 CEST 2013 on sn-devel-104
(cherry picked from commit
af290a03cef63c3b08446c1980de064a3b1c8804)