Fix lunch choices for git_main am: e8176bbf5e

Original change: https://android-review.googlesource.com/c/device/generic/trusty/+/2803044

Change-Id: Ib04f5412688b27d7642471038f28de153c44ac02
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>