Don't panic if no certificates found am: b7550aa0 am: 3495c736

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/2596605



Change-Id: Iec46e91b2141a0ecc46c526b2881f117d1f4e44d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>