Merge "keymaster: avoid deref'ing nullptr" am: 1e4630d844 am: a05e847177 am: 19361e0a7a am: 99d3ad54de

Original change: https://android-review.googlesource.com/c/platform/system/keymaster/+/1555467

Change-Id: I9d1e037b71ab7e08e20d7e7e86d2094484bf2998