Merge "Fix NPE in BootReceiver.addTombstoneToDropBox." into sc-qpr1-dev am: 94d3762fba am: a28c22fc1c

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15857254

Change-Id: Ica7b0d4e9692e5745906b35ab8e149bca6357f5e