Code review comment for lp:~nskaggs/juju-ci-tools/add-sane-args-defaults

Most changes seem fine, but we still have the test isolation issue from creating the logdir I pointed out before:

ubuntu@go:~/juju-ci-tools$ bzr st
modified:
  tests/test_utility.py
  utility.py
pending merge tips: (use -v to see all merge revisions)
  Nicholas Skaggs 2016-06-07 make temp_env_name truly unique

ubuntu@go:~/juju-ci-tools$ make test
...
FAILED (failures=2, errors=39)

ubuntu@go:~/juju-ci-tools$ bzr st
modified:
  tests/test_utility.py
  utility.py
unknown:
  baz/
  d/
  log/
  log_dir/
  test_utility_20160608144450_logs/
pending merge tips: (use -v to see all merge revisions)
  Nicholas Skaggs 2016-06-07 make temp_env_name truly unique