virt-v2v: testcases for converting vmware vms

Besides testcases, small but necessary changs are:
1. Set vm_type to v2v for v2v submodule
2. Recover missing lines for v2v and openvswitch.(Maybe lost it when merging lvsb)
3. Handle prompts for esx connection:
```
# virsh -c esx://xxx/?no_verify=1 list --all
Enter username for xxx [root]: 
Enter root's password for xxx: 
```