Minor cleanup of UsageStatsService

code cleanup, whitespaces

https://android-review.googlesource.com/#/c/92738/

Change-Id: Idea0e29f347d14e48e87aad38a261d0493bd5fd3
Signed-off-by: houst0nn <houstonn@gmail.com>
Merge "Minor cleanup of UsageStatsService" into kitkat