socket gethostbyaddr returns IPv6 names for 127.0.0.1

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2016-10-13.15:12:28.678>
labels = ['type-bug']
title = 'socket gethostbyaddr returns IPv6 names for 127.0.0.1'
updated_at = <Date 2016-10-13.15:24:53.526>
user = 'https://github.com/carbonin'

bugs.python.org fields:

activity = <Date 2016-10-13.15:24:53.526>
actor = 'r.david.murray'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2016-10-13.15:12:28.678>
creator = 'carbonin'
dependencies = []
files = []
hgrepos = []
issue_num = 28431
keywords = []
message_count = 2.0
messages = ['278580', '278582']
nosy_count = 2.0
nosy_names = ['r.david.murray', 'carbonin']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue28431'
versions = ['Python 2.7', 'Python 3.4']