vfs: update API interface to match new changes in chimera

Acked-by: Albert Rossi
(cherry picked from commit ffcf8a93596aa72aaac3a9b1a6eccbcfdfffce16)
Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
[maven-release-plugin] prepare release nfs4j-0.6.1