Merge pull request #38 from elastic/fix-test-start-date

Use date string for start date

Author: JoshMock

tests/machine_learning/start_stop_datafeed.yml

@@ -57,7 +57,7 @@ teardown:
   - do:
       ml.start_datafeed:
         datafeed_id: "start-stop-datafeed-datafeed-1"
-        start: 0
+        start: "1970-01-01T00:00:00.000Z"
   - do:
       ml.get_datafeed_stats:
         datafeed_id: "start-stop-datafeed-datafeed-1"