nfsd4: name->id mapping should fail with BADOWNER not BADNAME
According to rfc 3530 BADNAME is for strings that represent paths;
BADOWNER is for user/group names that don't map.
And the too-long name should probably be BADOWNER as well; it's
effectively the same as if we couldn't map it.
Cc: stable@kernel.org Reported-by: Trond Myklebust <Trond.Myklebust@netapp.com> Reported-by: Simon Kirby <sim@hostway.ca> Signed-off-by: J. Bruce Fields <bfields@redhat.com>