miner/worker: skip the uncle logic in Consortium

In Consortium consensus engine, we don't handle uncle blocks. Furthermore, the
uncle logic in worker may block the main creating block logic. So this commit
skips the uncle logic when Consortium consensus engine is used.

miner/worker.go

@@ -513,6 +513,10 @@ func (w *worker) mainLoop() {
 			w.commitNewWork(req.interrupt, req.noempty, req.timestamp)
 
 		case ev := <-w.chainSideCh:
+			// Don't handle uncle logic in Consortium
+			if w.chainConfig.Consortium != nil {
+				continue
+			}
 			// Short circuit for duplicate side blocks
 			if _, exist := w.localUncles[ev.Block.Hash()]; exist {
 				continue