Merge pull request #145 from aarondav/sls-fix

Attempt to fix SparkListenerSuite breakage

Could not reproduce locally, but this test could've been flaky if the build machine was too fast, due to typo. (index 0 is intentionally slowed down to ensure total time is >= 1 ms)

This should be merged into branch-0.8 as well.

(cherry picked from commit 951024feeadcf73b50c3c80ec9e75c7e2214a7a4)
Signed-off-by: Reynold Xin <rxin@apache.org>