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)
1 file changed