fix vmdriver test

tests/test.py

 #!/usr/bin/env python
 
+import os
+os.environ.setdefault("LIBVIRT_TEST", "True")
+
 import vm
 import vmdriver
 # import logging

vm.py

@@ -192,6 +192,7 @@ class VMDisk:
     target_device = None
 
     def __init__(self,
+                 name,
                  source,
                  disk_type="file",
                  disk_device="disk",
@@ -200,6 +201,7 @@ class VMDisk:
                  driver_cache="none",
                  target_device="vda",
                  target_bus="virtio"):
+        self.name = name
         self.source = source
         self.disk_type = disk_type
         self.disk_device = disk_device