libs: update nfs code to 0.7.2

The libdcap can distinct between regular file systems
and dCache's NFS. This is achieved by existence of a
magic file '.(get)(cursor)', which can be accessed in
any directory in dCache's namespace. Nevertheless, this
behaviour prevents dcap-aware clients to access dcache
through NFSv4.1.

The updated version of nfs library adds a possibility to
hide magic file from dcap client and force them to treat
dCache's NFS as a regular file system.

New export options added: dcap(defualt) and no_dcap.

Example:

/pnfs 10.0.1.1/24(rw,acl,no_dcap)

Changelog for nfs4j-0.7.1..nfs4j-0.7.2
    * [5c4808c] vfs: add a special option to hide dcache from dcap clients

Acked-by: Gerd Behrmann
Target: master, 2.7, 2.8
Require-book: yes
Require-notes: yes