Let the sync type be configurable.

Useful for setups where getting nfs sync working is a PITA.
Support adding multiple additional disks to gluster machines.

You can easily configure this by settings the disks integer in the
puppet-gluster.yaml file or with the --gluster-disks= parameter.

If this is set to the default of zero (0) then no disks are added.

This patch depends on:
https://github.com/pradels/vagrant-libvirt/issues/162
Pull operating system specific data from yaml files.

This patch includes package names.
Pull more operating system specific data from yaml files.

This patch includes program paths.
Add Debian/Ubuntu specific packaging changes.
Add Debian/Ubuntu specific service naming changes.

This patch also generalizes the service name, so that other operating
systems will also benefit from this patch by dropping in a yaml file.
Add Fedora/RedHat specific yaml data changes.

The Fedora changes are specific to F20 era changes. If you are
interested in having this compatible with an old version of Fedora, you
can drop in a Fedora version specific yaml file.
Use the correct path for findmnt on Fedora.

This patch is dedicated to Gilles who didn't like the findmnt patch
initially, but now loves it because it is cross distro friendly :)
Thanks for all your time testing Puppet-Gluster... More eyes helps!
Make argparse optional on platforms where it is built into python.
Documentation updates including yamldata multi-platform work.