Purge spam log when iorapd process is not alive.
Turn off the Iorap Service when both tracing and prefetching are not
alive.
Bug: 174588448
Test: set the flags via mendel and check the log
Change-Id: I8d4e0c869dec5e7dc5016622b154aef46e1d4f02
(cherry picked from commit 11b592be87)