Dispatch logic of WatchService ignores overlaping listeners

[splatch]

Report from @J-N-K

I just noticed that the OpenSmartHouse implementation has the same fault as the openHAB one: if a second Watchservice is registered for the same directory (or sub- or parent directory), the first one will not receive watch events.

Jan's fix for issue: https://github.com/smarthomej/addons/tree/3.1.x/bundles/org.smarthomej.commons/src/main/java/org/smarthomej/commons/service.

[cdjackson]

I did see this discussed in the OH repo. I'm happy if we want to cherry pick this in to OSH now if someone needs this fix - otherwise we probably need to pull over some of the updates and it will get swept up there.