s3: lib: nmblib. Clean up and harden nmb packet processing.

Jeremy Allisonrequested to merge
samba-team/devel/samba:jra-nmblib-bug-14239-1 into master

Seems to work now - passes CI.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14239

No security implications.

Signed-off-by: Jeremy Allison jra@samba.org Pair programmed with: Douglas Bagnall dbagnall@samba.org

Merge request reports