Similar to qemuxml2argv and storagevolxml2argv, let's create some
tests to ensure that the XML generates a consistent command line.

Using the same list of pools as storagepoolxml2xmltest, start with
the file system tests (fs, netfs, netfs-cifs, netfs-gluster).
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>
ACKed-by: NMichal Privoznik <mprivozn@redhat.com>