It's not sufficient to just look at swift.object-updater.successes to
see the async_pending unlink rate. There are two different spots where
unlinks happen: one when an async_pending has been successfully
processed, and another when the updater notices multiple
async_pendings for the same object. Both events are now tracked under
the same name: swift.object-updater.unlinks.
FakeLogger has now sprouted a couple of convenience methods for
testing logged metrics.
Fixed pep8 1.3.3's complaints in the files this diff touches.
Also: bonus speling and, grammar fixes in the admin guide.
Change-Id: I8c1493784adbe24ba2b5512615e87669b3d94505