libs: update nfs to 0.7.4

minor bugfix to support chimera's rename fixes

Changelog for nfs4j-0.7.3..nfs4j-0.7.4
    * [b11ec2a] nfs4: fix lookupp on the root of the tree
    * [f99922b] nfs4: fix handling of illegal operations
    * [5646570] vfs: chimera: translate exceptions to nfs errors

Acked-by: Gerd Behrmann
Target: master, 2.8, 2.7
Require-book: no
Require-notes: no
(cherry picked from commit fb72047265ae500fbdad0d26eef35d0028781339)
Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Merge pull request #441 from kofemann/nfs-0.7.4-2.7

libs: update nfs to 0.7.4