flask执行异常（light分支） #35
Description
在后台点击pass按钮时报调用栈：
10.254.0.252 - - [19/Mar/2017 21:10:32] "POST /pass/199 HTTP/1.1" 500 -
Traceback (most recent call last):
File "/usr/lib/python3.5/site-packages/flask/app.py", line 2000, in __call__
return self.wsgi_app(environ, start_response)
File "/usr/lib/python3.5/site-packages/flask/app.py", line 1991, in wsgi_app
response = self.make_response(self.handle_exception(e))
File "/usr/lib/python3.5/site-packages/flask/app.py", line 1567, in handle_exception
reraise(exc_type, exc_value, tb)
File "/usr/lib/python3.5/site-packages/flask/_compat.py", line 33, in reraise
raise value
File "/usr/lib/python3.5/site-packages/flask/app.py", line 1988, in wsgi_app
response = self.full_dispatch_request()
File "/usr/lib/python3.5/site-packages/flask/app.py", line 1641, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/usr/lib/python3.5/site-packages/flask/app.py", line 1544, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/usr/lib/python3.5/site-packages/flask/_compat.py", line 33, in reraise
raise value
File "/usr/lib/python3.5/site-packages/flask/app.py", line 1639, in full_dispatch_request
rv = self.dispatch_request()
File "/usr/lib/python3.5/site-packages/flask/app.py", line 1625, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/usr/lib/python3.5/site-packages/flask_login.py", line 792, in decorated_view
return func(*args, **kwargs)
File "/srv/lugvpn-web/app/views.py", line 163, in pass_
send_mail('Your application has passed', html, user.email)
File "/srv/lugvpn-web/app/mail.py", line 11, in send_mail
mail.send(msg)
File "/usr/lib/python3.5/site-packages/flask_mail.py", line 491, in send
with self.connect() as connection:
File "/usr/lib/python3.5/site-packages/flask_mail.py", line 144, in __enter__
self.host = self.configure_host()
File "/usr/lib/python3.5/site-packages/flask_mail.py", line 158, in configure_host
host = smtplib.SMTP(self.mail.server, self.mail.port)
File "/usr/lib/python3.5/smtplib.py", line 251, in __init__
(code, msg) = self.connect(host, port)
File "/usr/lib/python3.5/smtplib.py", line 335, in connect
self.sock = self._get_socket(host, port, self.timeout)
File "/usr/lib/python3.5/smtplib.py", line 306, in _get_socket
self.source_address)
File "/usr/lib/python3.5/socket.py", line 693, in create_connection
for res in getaddrinfo(host, port, 0, SOCK_STREAM):
File "/usr/lib/python3.5/socket.py", line 732, in getaddrinfo
for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
socket.gaierror: [Errno -3] Try again
有时间看一下吗？ @zzh1996