virt: Multi-host repair compatibility with new virt cfg structure.

Signed-off-by: Jiří Župka <jzupka@redhat.com>
virt: Adds test for vhost and adds minor repair for file transfer tests.

vhost test: tests for migration with different vhost param setup.
repair: multi-host file transfer test. The test correctly delete all files
        which are used for testing and adds parameter for "del_file_with_err"
        control deleting of files used for testing.

Signed-off-by: Jiří Župka <jzupka@redhat.com>
virt: cartesian_config catch another cfg error.

Signed-off-by: Jiří Župka <jzupka@redhat.com>