Minor Fix in NetworkStatsService

Fix mistakes pointed out in
aosp/3195840 and aosp/3115462:
1. typo of bug id in comments
2. removal of unused funtion
3. removal of redundant blank lines

Test: TH
Bug: 343844995
Change-Id: I932e766c76e9a194d6718f3929bd50215d0b55cb
1 file changed