virtinst: connection: Drop is_closed() helper

We have is_open, just use that

Signed-off-by: Cole Robinson <crobinso@redhat.com>

tests/test_conn.py

@@ -28,7 +28,6 @@ class TestConn(unittest.TestCase):
         assert not conn.get_uri_username()
         assert not conn.get_uri_transport()
         assert conn.close() == 0
-        assert conn.is_closed()
 
         # Coverage for a daemon_version check
         fakeuri = "__virtinst_test__test:///default,libver=123"

virtManager/connection.py

@@ -840,7 +840,7 @@ class vmmConnection(vmmGObject):
         self._closing = True
 
         try:
-            if not self._backend.is_closed():
+            if self._backend.is_open():
                 for eid in self._domain_cb_ids:
                     self._backend.domainEventDeregisterAny(eid)
                 for eid in self._network_cb_ids:

virtinst/connection.py

@@ -124,9 +124,6 @@ class VirtinstConnection(object):
     # Public API #
     ##############
 
-    def is_closed(self):
-        return not bool(self._libvirtconn)
-
     def close(self):
         ret = 0
         if self._libvirtconn: