Shore up the implementation of copyfile_sparse

Signed-off-by: Chris Lalancette <clalancette@gmail.com>
Make the RPM spec file depend on libvirt-daemon-config-network

As pointed out by giulivo, current RPM distributions
will not start the default network without
libvirt-daemon-config-network installed.  While it is
possible to use Oz without this default network, I think
that most users would be happier to have it installed.
Make oz depend on libvirt-daemon-config-network.

Signed-off-by: Chris Lalancette <clalancette@gmail.com>
Add file exists check to copyfile_sparse

In acbb467709ce43b9c16b0ad2f5e025533fe8505c a os.path.samefile was added but no checks on if dest / src exist prior to it.
This is problematic especially when the destination file does not exist already. Now it only runs samefile when a dest already exists.
Move some common linux stuff into linuxutil

Signed-off-by: Chris Lalancette <clalancette@gmail.com>
Remove unnecessary bootloader lines in Fedora

Signed-off-by: Chris Lalancette <clalancette@gmail.com>
Add support for Ubuntu 13.04

Signed-off-by: Chris Lalancette <clalancette@gmail.com>
Warn instead of failing when given libvirt_xml with more than one disk

Oz itself never generates libvirt XML with more than one disk.

Allowing users to pass in modified guests at their own risk allows
for some interesting use cases.

The one I'm specifically interested in involves using Image Factory
plus Oz to drive the creation of Live CD images entirely inside of
VMs.
Fixes to improve pylint score

Signed-off-by: Chris Lalancette <clalancette@gmail.com>