Use mContext directly, and enforce via logging

We already have the context saved, so we can just use that.
Add a log statement so we can test for the existence of this patch from
a CTS test.

Test: Edited code to force expection path to be called, confirmed
      reboot happens
Bug: 138952436
Bug: 140111727

Change-Id: Iaceec82d4716837158d1233400b4a44cbf67a5e8