When nfsrv_checksequence() replies NFSERR_BADSLOT,
the value of nd_slotid is not valid.  As such, the
reply cannot be cached in the session.
Do not set ND_HASSEQUENCE for this case.

Reported by:	rtm@lcs.mit.edu
Tested by:	rtm@lcs.mit.edu
PR:	260076
MFC after:	2 weeks