NFS: Map minor mismatch error to protocol not support error.

Sservers that only have NFSv4.1 support the
NFS4ERR_MINOR_VERS_MISMATCH error is return on
v4.0 mounts. Mapping that error to EPROTONOSUPPORT
will cause the mount to back off to v3 instead of
failing.
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4proc.c

@@ -105,6 +105,8 @@ static int nfs4_map_errors(int err)
 		return -EINVAL;
 	case -NFS4ERR_SHARE_DENIED:
 		return -EACCES;
+	case -NFS4ERR_MINOR_VERS_MISMATCH:
+		return -EPROTONOSUPPORT;
 	default:
 		dprintk("%s could not handle NFSv4 error %d\n",
 				__func__, -err);