Simplify the print message of rolling output feature am: 01ff150be9

Original change: https://android-review.googlesource.com/c/platform/tools/asuite/+/3414161

Change-Id: I59e2351beb5eebf0d0cfeb4c1edb3d8b9ae24bf0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>