StatsCompanionService logcat message updates

StatsCompanionService logs that it cannot find statsd, but
since it never says when it succeeds, it looks worrisome.
It's useful to know, so both outcomes are now logged.
Other minor logging changes are done too.

Bug: 73495509
Test: none
Change-Id: I67236b8d323751d0c5e3fa2454eccceb8c4250a0