Simplify bool parsing am: 8aa7e9be3e am: 631fdff301

Original change: https://android-review.googlesource.com/c/platform/system/librustutils/+/2571571

Change-Id: I35eaa2f478d4e0d8fbefbfecfead2146f3c06c3e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>