nfs: Update to version 2.7.1

- Update from version 2.6.4 to 2.7.1
- Update of rootfile
- Changelog is a list of all the commits and it is made available in the file
   2.7.1-Changelog in the sourceforge site
    https://sourceforge.net/projects/nfs/files/nfs-utils/2.7.1/

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

config/rootfiles/packages/nfs

@@ -37,6 +37,7 @@ usr/sbin/nfsdclddb
 usr/sbin/nfsdclnts
 usr/sbin/nfsidmap
 usr/sbin/nfsiostat
+usr/sbin/nfsref
 usr/sbin/nfsstat
 usr/sbin/rpc.idmapd
 usr/sbin/rpc.mountd
@@ -70,6 +71,7 @@ usr/sbin/start-statd
 #usr/share/man/man8/nfsdcltrack.8
 #usr/share/man/man8/nfsidmap.8
 #usr/share/man/man8/nfsiostat.8
+#usr/share/man/man8/nfsref.8
 #usr/share/man/man8/nfsstat.8
 #usr/share/man/man8/rpc.idmapd.8
 #usr/share/man/man8/rpc.mountd.8