Floss: Add constraint to service watcher to match service name

When watching for a certain interface to be added, we also want to
restrict the service who emits the InterfacesAdded signal. In D-Bus we
can't just detect whether the sender has the specified service name, but
we need to keep track the owner D-Bus address of the service we are
watching to be able to match the signal with the emitting service.

Bug: 224606285
Tag: #floss
Test: Manual - Ran btmanagerd on Linux

Change-Id: I6dbf3f337ba3a281086e9f509e16c2de98cf4f0e