Decrease number of network logging notifications shown

Now, network logging will show one notification when it is enabled
and one after the next reboot.

Bug: 36254499
Test: CTS Verifier > Managed Provisioning > Device Owner Tests
      > Network Logging UI

Change-Id: I60fc64e96ceb0ec0ae7ca832b74ac8b47e581be4
(cherry picked from commit 55dba53e)