Implement keystore2 logging of key creation events.

This CL implements logging of key creation events via statsd.

Bug: 172013262
Test: enable keystore2 on cuttlfish, run cts tests for key generation,
run the test drive script provided by statsd and observe the logs
created.

Change-Id: Ib60ed356ce809d27f7625ab0743a9300c454f1c8
5 files changed