Merge "Removing BOARD_BUILD_SYSTEM_ROOT_IMAGE" am: 239ab9e265

Original change: https://android-review.googlesource.com/c/device/generic/common/+/2063543

Change-Id: Iede589f951f0b1f5f3e104d6b1ff8e415e35d966
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>