configurable disk_bus

Signed-off-by: Hiroshi Miura <miurahr@linux.com>
add spec for config

Signed-off-by: Hiroshi Miura <miurahr@linux.com>
template: ide should be on pci00:00:01.1

Signed-off-by: Hiroshi Miura <miurahr@linux.com>
Merge branch 'diskbus_config' into next

Conflicts:
	README.md
	templates/libvirt_domain.erb