Cleaning up topoSetupRcvd

Converted it to a boolean updatingTopo. The only change from before is
that setFailed sets this to false only if we are updating topology(CAS).
This guarantees that we don't hit the same deadlock - when multiple
tasks are to update topology but by the time the stage gets to one of
the tasks, it fails & also restarts. We feel since the task is now
running, it must have received UpdateTopology while the task indeed
failed & did not.