Fix null IpmemoryService object in AGO project.

WTF will happen in RegularMaintenanceJobService due to
scheduling job and starting maintenance job are in different
processes. In AGO project, scheduling job use inprocess process.
But starting maintenance job use networkstack process. So
IpmemoryService objcet will be null when trying to do the
maintenance job.

Bug: 132763800
Test: Verify on both AGO and non-AGO projects that WFT will not
      happen.
Test: atest NetworkStackTests

Change-Id: I29ea1710b45b8aef697b84e17e793ba9b2cab490