autotest: rpc_flight_recorder measure in milliseconds

BUG=chromium:772250
TEST=None

Change-Id: I6842b4a3548aea3209a38e54944fb6506b69fc17
Reviewed-on: https://chromium-review.googlesource.com/704077
Commit-Ready: Aviv Keshet <akeshet@chromium.org>
Tested-by: Aviv Keshet <akeshet@chromium.org>
Reviewed-by: Prathmesh Prabhu <pprabhu@chromium.org>
diff --git a/site_utils/rpc_flight_recorder.py b/site_utils/rpc_flight_recorder.py
index bd9e88c..8fc7b57 100755
--- a/site_utils/rpc_flight_recorder.py
+++ b/site_utils/rpc_flight_recorder.py
@@ -225,7 +225,7 @@
         metric_fields['failure_reason'] = ''
 
         with metrics.SecondsTimer(METRIC_RPC_CALL_DURATIONS,
-                fields=dict(metric_fields)) as f:
+                fields=dict(metric_fields), scale=0.001) as f:
 
             msg_str = "%s:%s" % (self._hostname, cmd)