[test-infra] Need to clear the progressbar to 0% when start the test (#1018)

The progress bar also show done(100%) after restart it with only test manual cases, 
We need to clear its  status to 0%

View on GitHub: https://github.com/w3c/web-platform-tests/pull/1018

Received on Tuesday, 27 May 2014 03:21:27 UTC