Update chromeos_factory to pass masters_cfg_test.py.
Update chromeos_factory to pass masters_cfg_test.py.

Followup to https://codereview.chromium.org/1229833005/

BUG=chromium:497958
TEST=Run tests/masters_cfg_test.py

Review URL: https://codereview.chromium.org/1256993006 .

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@296146 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build