travis CI failed for all pull request

[xialu4820723]

This was caused by some invalid urls detected by awesome_bot, they were listed below

Link issues by awesome_bot

Line	Status	Link
200	301	http://pyvideo.org/video/2608/flask-by-example/ redirects to https://pyvideo.org/video/2608/flask-by-example/
201	301	http://pyvideo.org/video/2668/writing-restful-web-services-with-flask/ redirects to https://pyvideo.org/video/2668/writing-restful-web-services-with-flask/
209	502	https://python-china.org_
221	404	https://github.com/vinceprignano/chatapp