MFC: r268273
The new NFSv3 server did not generate directory postop attributes for
the reply to ReaddirPlus when the server failed within the loop
that calls VFS_VGET(). This failure is most likely an error
return from VFS_VGET() caused by a bogus d_fileno that was
truncated to 32bits.
This patch fixes the server so that it will return directory postop
attributes for the failure. It does not fix the underlying issue caused
by d_fileno being uint32_t when a file system like ZFS generates
a fileno that is greater than 32bits.

(cherry picked from commit aa183af4c50f5e86138c443fa9a0513a226d2d27)

Ticket: #7186
(cherry picked from commit 4f22fef4143b6af50e229514f6a5238ef43947ae)