Sped up tests by using smaller files

Switched one of the disk file tests to use a smaller file size for
testing. The larger size was not needed and accounted for ~3% of the
total test time by itself.

Change-Id: Ie71a390117baa2d286122a46880a4558f50b83b9
Add unit test for account/auditor.py

* Here lack tests for a long time; let's add tests for it.
* use mock module instead of monkeypatch in both account/test_auditor.py
  and container/test_auditor.py

Change-Id: I9ea23dc5034f7147629db59b1ef6cb491de9049f
Merge "Sped up tests by using smaller files"
Merge "Add unit test for account/auditor.py"