We only recorded the last received event (which is needed when a sensor
is activated on a connection) when there was some connection active.
This should fix an issue where sometimes the light sensor doesn't
return an event whent activated.
we also didn't need to hold the main lock while dispatching events
to clients.
Change-Id: I6c6386c040051ce205e3c0516c678e0603fa45e1
3a9223ebf8