wifi: Use @SystemApi UserHandle.SYSTEM

Use the already formal API to get the user id for the default system
user.

Bug: 147396785
Test: atest com.android.server.wifi
Test: Device boots up & connects to wifi networks.
Change-Id: I400557de1baff1fdf5d49c8402d1f2bf7a320072
2 files changed
tree: bb520335dd2a9b73591ee60c12e39311d408c6df
  1. apex/
  2. service/
  3. PREUPLOAD.cfg