Merge "Revert "libprocessgroup: return false on failure"" am: a2b180ab64 am: cfad863a9f am: 580548b443

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2061121

Change-Id: I5757ad72ca70daad64681d4bd80ac7691a5c8c03
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>