webbrowser.open outputs xdg-open deprecation warning

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2017-05-01.12:34:17.421>
labels = ['type-bug', 'library']
title = 'webbrowser.open outputs xdg-open deprecation warning'
updated_at = <Date 2017-05-12.20:31:16.055>
user = 'https://github.com/desbma'

bugs.python.org fields:

activity = <Date 2017-05-12.20:31:16.055>
actor = 'desbma'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2017-05-01.12:34:17.421>
creator = 'desbma'
dependencies = []
files = ['46845']
hgrepos = []
issue_num = 30219
keywords = ['patch']
message_count = 12.0
messages = ['292659', '292666', '292742', '292743', '293455', '293461', '293490', '293491', '293514', '293544', '293546', '293569']
nosy_count = 3.0
nosy_names = ['vstinner', 'serhiy.storchaka', 'desbma']
pr_nums = []
priority = 'normal'
resolution = 'third party'
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue30219'
versions = ['Python 3.6']