[2300] set self.tsig_key_name in XfrinConnection.__init__()

Because this is used for outputting an error message when failing to connect to
master. (This is not a related change.)

src/bin/xfrin/tests/xfrin_test.py

@@ -3486,7 +3486,8 @@ class TestXfrinConnectionSocketCounter(unittest.TestCase):
         try:
             self.assertRaises(self.expception, self.conn.connect,
                               self._master_addrinfo[2])
-            self.assertEqual(1, self.conn._counters.get(
+            self.assertFalse(self.conn.connect_to_master())
+            self.assertEqual(2, self.conn._counters.get(
                     'socket', self._ipver, 'tcp', 'connfail'))
         finally:
             xfrin.asyncore.dispatcher.connect = orig_socket_connect

src/bin/xfrin/xfrin.py.in

@@ -610,6 +610,11 @@ class XfrinConnection(asyncore.dispatcher):
         self._shutdown_event = shutdown_event
         self._master_addrinfo = master_addrinfo
         self._tsig_key = tsig_key
+        # self.tsig_key_name is used for outputting an error massage in
+        # connect_to_master().
+        self.tsig_key_name = None
+        if tsig_key:
+            self.tsig_key_name = self._tsig_key.get_key_name()
         self._tsig_ctx = None
         # tsig_ctx_creator is introduced to allow tests to use a mock class for
         # easier tests (in normal case we always use the default)