s3: smbd: init_smb1_request() isn't being passed zero'ed memory from any codepath.

s3: smbd: init_smb1_request() isn't being passed zero'ed memory from any codepath.

If a client does a SMB1 NEGPROT followed by SMB1 TCON
then req->session is left uninitialized.

Show this causes a crash by deliberately initializing
req->session to an invalid pointer. This will be removed
once the test shows the crash, and the fix is added to
cause init_smb1_request() to zero the memory passed in.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15432

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Noel Power <npower@samba.org>
(Back-ported from commit f02f74e931f5821c7b7c1be2b8f0fb60c9a69b19)