QA:Testcase Stable PCI Addresses When Adding Device For Linux Guest

Description

What does this test case do?

How to test

1. Start a linux guest with one PCI NICs (such as: 8139 model)
2. Note the PCI slot numbers of the NIC in guest using lspci command.
3. Shutdown the guest
4. Add the 2th NIC (such as: e1000 model) and start the guest

Expected Results

1. Check that the slot number of the 1th NIC hasn't changed, and guest is working fine.