Polished mgr query handoff from the original recepient worker to Coordinator.

Polished mgr query handoff from the original recepient worker to Coordinator.

When the worker receives a cache manager query, gives it to Coordinator, and
receives an ACK from Coordinator, the worker should stop handling the
originating transaction without declaring the associated StoreEntry as
complete because doing so triggers store client activity on the client-side
and might cause undesirable output to the now-shared HTTP client socket.
Besides, declaring an empty entry as complete is kind of wrong.