Add address attribute in DiskSource

[chunfuwen]

Add address attribute in DiskSource

In some scenario, it need enable address attributes something like below for DiskSource

   <source type='pci' managed='yes' namespace='1' index='1'>
      <address domain='0x0000' bus='0x17' slot='0x00' function='0x0'/>
   </source>

Signed-off-by: chunfuwen [email protected]

[chunfuwen]

some basic unit testing result:

>>> from virttest.libvirt_xml.devices.disk import Disk
>>> disk = Disk()
>>> disk_src_dict = {"attrs": {"file": '/var/lib/libvirt/images/test.qcow2'}}
>>> disk_source = disk.new_disk_source(**disk_src_dict)
>>> disk_source.address = {'domain':'0x0000', 'bus':'0x17', 'slot':'0x00', 'function':'0x0'}
>>> disk.source = disk_source
>>> print(disk)
<?xml version='1.0' encoding='UTF-8'?>
<disk type="file"><source file="/var/lib/libvirt/images/test.qcow2"><address bus="0x17" domain="0x0000" function="0x0" slot="0x00" /></source></disk>
>>> 

[chunfuwen]

@dzhengfy please take a look