s3: libsmb: Fix valgrind read-after-free error in cli_smb2_close_fnum_recv().

s3: libsmb: Fix valgrind read-after-free error in cli_smb2_close_fnum_recv().

cli_smb2_close_fnum_recv() uses tevent_req_simple_recv_ntstatus(req), which
frees req, then uses the state pointer which was owned by req.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13171

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Ralph Böhme <slow@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Thu Nov 30 05:47:12 CET 2017 on sn-devel-144

(cherry picked from commit 5c8032b6b8ce4439b3ef8f43a62a419f081eb787)

Autobuild-User(v4-6-test): Karolin Seeger <kseeger@samba.org>
Autobuild-Date(v4-6-test): Tue Dec  5 14:29:20 CET 2017 on sn-devel-144