[automerger] Fix a memory leak in gatekeeper. am: 6a9c4e7968 am: bdc924f31d am: 7535975701 am: e126026c02 am: 4ae4ad8e5b
am: b25983460c

Change-Id: Ie7a02bb3c7b283f3497a469e0cd3b2b69792d2f6