Revert "Merge branch 'SlaveInfo' of git://github.com/jaredgrubb/buildbot"

This reverts commit 1c5973413aa3b7e5f2f197b488cd58206b7ac057, reversing
changes made to bf5c148e7b427c1f685ce846696a90ed2dc24704.

See https://github.com/buildbot/buildbot/pull/880 for details on why
this was reverted.

Conflicts:
	master/buildbot/status/slave.py
	master/docs/relnotes/index.rst