When a stale file handle is encountered, purge all cached information about
an NFS node including the access and attribute caches. Previously the NFS
client only purged any name cache entries associated with the file.

PR: kern/123755
Submitted by: Jaakko Heinonen jh of saunalahti fi
Reported by: Timo Sirainen tss of iki fi
Reviewed by: rwatson, rmacklem
MFC after: 1 month