Make pylint happy

- Drop unused 'asyncio'
- Drop useless 'else' after return

(cherry picked from commit 43786e1)

qubes/vm/qubesvm.py

@@ -631,8 +631,8 @@ def xid(self):
         try:
             if self.is_running():
                 return self.libvirt_domain.ID()
-            else:
-                return -1
+
+            return -1
         except libvirt.libvirtError as e:
             if e.get_error_code() == libvirt.VIR_ERR_NO_DOMAIN:
                 return -1