nfsd: don't drop requests on -ENOMEM

We never want to drop a request if we could return a JUKEBOX/DELAY error
instead; so, convert to nfserr_jukebox and let nfsd_dispatch() convert
that to a dropit error as a last resort if JUKEBOX/DELAY is unavailable
(as in the NFSv2 case).
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfsproc.c

@@ -736,7 +736,7 @@ nfserrno (int errno)
 		{ nfserr_jukebox, -ETIMEDOUT },
 		{ nfserr_jukebox, -ERESTARTSYS },
 		{ nfserr_dropit, -EAGAIN },
-		{ nfserr_dropit, -ENOMEM },
+		{ nfserr_jukebox, -ENOMEM },
 		{ nfserr_badname, -ESRCH },
 		{ nfserr_io, -ETXTBSY },
 		{ nfserr_notsupp, -EOPNOTSUPP },