nfsm_srvnamesiz() may set up an NFSERR_NAMETOL error, which nfsm_reply() would

nfsm_srvnamesiz() may set up an NFSERR_NAMETOL error, which nfsm_reply() would
consider as not tragic enough to abort the operation, in order to batch error
replies.

This would end up invoking nfs_namei() using an uninitialized variable as
length, and Bad Things(TM) would happen.

Reported by Claes M Nyberg on bugs@; tweaks & ok claudio@