devel/py-buildbot*: Update to 2.7.0

devel/py-buildbot:

• Remove setup.py patch (upstreamed)
• Update test target (setup.py test is going away :|)

Changelog:

https://docs.buildbot.net/current/relnotes/index.html#buildbot-2-7-0-2020-02-27

PR: 244219