salt: salt-minion AttributeError: 'AsyncAuth' object has no attribute '_finger_fail'

Here is a bug I encounter when setting master_finger option in minion config:

    ➜  ~  cat /etc/salt/minion
    master: 127.0.0.1
    master_finger: 02:2b:e6:4e:d8:67:c2:1a:e2:3b:76:b9:76:4c:0c:1b

    ➜  ~  salt-minion --version
    salt-minion 2015.8.1 (Beryllium)

    ➜  ~  sudo salt-minion --log-level debug
    [DEBUG   ] Reading configuration from /etc/salt/minion
    [DEBUG   ] Using cached minion ID from /etc/salt/minion_id: vagrant-gt
    [DEBUG   ] Configuration file path: /etc/salt/minion
    [WARNING ] Insecure logging configuration detected! Sensitive data may be logged.
    [INFO    ] Setting up the Salt Minion "vagrant-gt"
    [DEBUG   ] Created pidfile: /var/run/salt-minion.pid
    [DEBUG   ] Reading configuration from /etc/salt/minion
    [DEBUG   ] Please install 'virt-what' to improve results of the 'virtual' grain.
    [INFO    ] The salt minion is starting up
    [INFO    ] Minion is starting as user 'root'
    [DEBUG   ] AsyncEventPublisher PUB socket URI: ipc:///var/run/salt/minion/minion_event_1c5498977f_pub.ipc
    [DEBUG   ] AsyncEventPublisher PULL socket URI: ipc:///var/run/salt/minion/minion_event_1c5498977f_pull.ipc
    [INFO    ] Starting pub socket on ipc:///var/run/salt/minion/minion_event_1c5498977f_pub.ipc
    [INFO    ] Starting pull socket on ipc:///var/run/salt/minion/minion_event_1c5498977f_pull.ipc
    [DEBUG   ] Minion 'vagrant-gt' trying to tune in
    [DEBUG   ] sync_connect_master
    [DEBUG   ] Initializing new SAuth for ('/etc/salt/pki/minion', 'vagrant-gt', 'tcp://127.0.0.1:4506')
    [DEBUG   ] Generated random reconnect delay between '1000ms' and '11000ms' (10320)
    [DEBUG   ] Setting zmq_reconnect_ivl to '10320ms'
    [DEBUG   ] Setting zmq_reconnect_ivl_max to '11000ms'
    [DEBUG   ] Initializing new AsyncZeroMQReqChannel for ('/etc/salt/pki/minion', 'vagrant-gt', 'tcp://127.0.0.1:4506', 'clear')
    [DEBUG   ] Decrypting the current master AES key
    [DEBUG   ] Loaded minion key: /etc/salt/pki/minion/minion.pem
    [ERROR   ] Exception in callback <functools.partial object at 0x7f8cb46e8940>
    Traceback (most recent call last):
      File "/usr/local/lib/python2.7/dist-packages/tornado/ioloop.py", line 592, in _run_callback
    ret = callback()
      File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 275, in null_wrapper
    return fn(*args, **kwargs)
      File "/usr/local/lib/python2.7/dist-packages/tornado/ioloop.py", line 598, in <lambda>
    self.add_future(ret, lambda f: f.result())
      File "/usr/local/lib/python2.7/dist-packages/tornado/concurrent.py", line 215, in result
    raise_exc_info(self._exc_info)
      File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 876, in run
    yielded = self.gen.throw(*exc_info)
      File "/usr/lib/python2.7/dist-packages/salt/crypt.py", line 432, in _authenticate
    creds = yield self.sign_in()
      File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 870, in run
    value = future.result()
      File "/usr/local/lib/python2.7/dist-packages/tornado/concurrent.py", line 215, in result
    raise_exc_info(self._exc_info)
      File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 879, in run
    yielded = self.gen.send(value)
      File "/usr/lib/python2.7/dist-packages/salt/crypt.py", line 562, in sign_in
    self._finger_fail(self.opts['master_finger'], m_pub_fn)
    AttributeError: 'AsyncAuth' object has no attribute '_finger_fail'