AudioService: fix devices for strategy APIs log

Remove duplicated log in AudioDeviceInventory for preferred
devices for strategy APIs.

Also do not log an error when removing a preferrence that was not set
before: this is a noop and does not need to be logged as an error.

Test: make.
Change-Id: I7b227eca7e55efe9b30403e0a73ce4eb8730b6d8