am a6247469: Merge "keystore: allow system to clear keys even while encrypted" into lmp-dev

* commit 'a62474699a202588609d7051e677f23734151900':
  keystore: allow system to clear keys even while encrypted
tree: c8047628401f1511fde644634a206d5b28ecb73d
  1. keystore/
  2. keystore-engine/
  3. softkeymaster/