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 "Fix swift-recon --auditor bug"