samba3.blackbox.smbclient_auth.plain: Add new regression test case.

samba3.blackbox.smbclient_auth.plain: Add new regression test case.

Test case covers commit:
96a49d23a4caebefcea66cfb855fadbae12ccf7c

Test case covers segfault of smbclient binary when
client NTLMv2 auth = yes
client use spnego = no
client max protocol = NT1
options are used.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11793
RH BUG: http://bugzilla.redhat.com/show_bug.cgi?id=1271763

How to test:
$ make -j test TESTS="samba3.blackbox.smbclient_auth.plain"
RESULD: Should PASS
$ git revert 96a49d23a4caebefcea66cfb855fadbae12ccf7c
$ make -j test TESTS="samba3.blackbox.smbclient_auth.plain"
RESULT: Should FAIL
(and you can see segfault in dmesg)

Signed-off-by: Robin Hack <rhack@redhat.com>
Reviewed-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Wed Mar 16 18:29:10 CET 2016 on sn-devel-144