Recent versions of Ceph allow calling the NFS-export management
functions over the go-ceph API.
This seems incompatible with older versions that have been tested with
the `ceph nfs` commands that this commit replaces.
Signed-off-by: Niels de Vos <ndevos@redhat.com>
(cherry picked from commit 28369702d275381b559f77c7e38adf599128e457)