Add a fake hwservicemanager for running w/o hwservicemanager

If hwservicemanager is not installed on a device, we can return this
fake hwservicemanager instance when clients ask for it.
This instance doesn't do anything when used, but allows client code to
remain the same to support devices that still have hwservicemanager

Bug: 218588089
Test: boot cuttlefish with and without hwservicemanager

Change-Id: Ie8efbaad0e6b1d399f54ffb73a8a58334afe535f
1 file changed