VMware: Fix deletion of an instance with no files

When a managed object doesn't contain a property, RetrievePropertiesEx
doesn't return None; it doesn't return the property at all. We were
testing for this incorrectly and not handling it in the code.

Change-Id: I77a0ba4eb5a6cc6075db9c67294f30abaa0e474d

nova/tests/virt/vmwareapi/fake.py

@@ -242,6 +242,10 @@ class ManagedObject(object):
         """
         return self.__getattr__(attr)
 
+    def delete(self, attr):
+        """Deletes an attribute."""
+        self.propSet = filter(lambda elem: elem.name != attr, self.propSet)
+
     def __setattr__(self, attr, val):
         # TODO(hartsocks): this is adds unnecessary complexity to the class
         for prop in self.propSet:

nova/tests/virt/vmwareapi/test_driver_api.py

@@ -1444,9 +1444,9 @@ class VMwareAPIVMTestCase(test.NoDBTestCase):
         self._check_vm_info(info, power_state.RUNNING)
         instances = self.conn.list_instances()
         self.assertEqual(len(instances), 1)
-        # Overwrite the vmPathName
+        # Delete the vmPathName
         vm = self._get_vm_record()
-        vm.set("config.files.vmPathName", None)
+        vm.delete('config.files.vmPathName')
         self.conn.destroy(self.context, self.instance, self.network_info)
         instances = self.conn.list_instances()
         self.assertEqual(len(instances), 0)

nova/virt/vmwareapi/vmops.py

@@ -771,10 +771,12 @@ class VMwareVMOps(object):
             query = vm_util.get_values_from_object_properties(
                     self._session, props)
             pwr_state = query['runtime.powerState']
-            vm_config_pathname = query['config.files.vmPathName']
+
+            vm_config_pathname = query.get('config.files.vmPathName')
             vm_ds_path = None
-            if vm_config_pathname:
-                vm_ds_path = ds_util.DatastorePath.parse(vm_config_pathname)
+            if vm_config_pathname is not None:
+                vm_ds_path = ds_util.DatastorePath.parse(
+                        vm_config_pathname)
 
             # Power off the VM if it is in PoweredOn state.
             if pwr_state == "poweredOn":