logwrap: Change semantics of NULL status in android_fork_execvp

When passing a NULL status to android_fork_execvp the return
status will now be the return value of the child if it exited
properly, otherwise a non-0 value will be returned.

Change-Id: I13309c61b37b6b3f9d5507f7d6484e7b6baaf8d0
2 files changed