multiprocessing Server's shutdown method useless send message to manager

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2017-11-13.06:00:30.342>
labels = ['type-bug', 'library']
title = "multiprocessing Server's shutdown method useless send message to manager"
updated_at = <Date 2017-11-13.06:00:30.342>
user = 'https://github.com/subler'

bugs.python.org fields:

activity = <Date 2017-11-13.06:00:30.342>
actor = 'stevezh'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2017-11-13.06:00:30.342>
creator = 'stevezh'
dependencies = []
files = []
hgrepos = []
issue_num = 32014
keywords = []
message_count = 1.0
messages = ['306142']
nosy_count = 5.0
nosy_names = ['pitrou', 'jnoller', 'sbt', 'davin', 'stevezh']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue32014'
versions = ['Python 3.5', 'Python 3.6']