Fix some spelling in comments

Change-Id: Id272dd9f603a42d9b22f80cff93716a5ed15698a
Don't count 412 or 416 as errors in stats

The backend HTTP servers emit StatsD metrics of the form
<server>.<method>.timing and <server>.<method>.errors.timing
(e.g. object-server.GET.timing). Whether something counts as an error
or not is based on the response's HTTP status code.

Prior to this commit, "success" was 2xx, 3xx, or 404, while everything
else was considered "error". This adds 412 and 416 to the "success"
set. Like 404, these status codes indicate that we got the request and
processed it without error, but the response was "no". They shouldn't
be in the same category as statuses like 507 that indicate something
stopped the request from being processed.

Change-Id: I5582a51cf6f64aa22c890da01aaaa077f3a54202
Fix swift-recon --auditor bug

I introduced a bug in swift-recon --auditor, which Christian
Schwede uncovered.  Christian proposed a fix which replaces the
generator nested_get_value with a recursive function which
returns just one instance of a key.  Christian's fix will break
the parallel object auditor patch which uses the generator to
return all instances of a particular key in a nested dictionary
and then sums those values.

This alternative fix sums over all values returned by
nested_get_value, as is done in the parallel auditor patch.

Change-Id: I6ac403395ab42d11161d6df266e8fbd5a2af9a64
Merge "Don't count 412 or 416 as errors in stats"
Merge "Fix swift-recon --auditor bug"
Merge "Fix some spelling in comments"