Fail if coverage < 100%.
Merge pull request #377 from tseaver/fail-coverage_lt_100_pct

Fail if coverage < 100%.
Revert "Fail if coverage < 100%."
Merge pull request #378 from GoogleCloudPlatform/revert-377-fail-coverage_lt_100_pct

Revert "Fail if coverage < 100%."