s3: Fix the async echo responder for netbios keepalives
This fixes a crash in the echo responder when the client started to send the
NetBIOS-Level 0x85-style keepalive packets. We did not correctly check the
packet length, so the code writing the signing seqnum overwrote memory after
the malloc'ed area for the 4 byte keepalive packet.
Autobuild-User: Jeremy Allison <jra@samba.org>
Autobuild-Date: Thu Oct 7 19:47:35 UTC 2010 on sn-devel-104