Remove potential double free Janis noticed that GetAuthTokenKey has ownership retained by the implementer, but the caller in libgatekeeper is delete[]ing it. Bug: 120610663 Bug: 129768470 Test: gatekeeper-unit-tests, Gatekeeper 1.0 VTS against Trusty Change-Id: I67171d707706b1ebe5caad47447762144495e28b (cherry picked from commit 6d2ee18a9af8eb9d8580850e434d21e4481fa36e) (cherry picked from commit 303e6db4d5fbdd42be5bfda1419c759f8e8e4626)