core, miner: remove Frontier canary

miner/worker.go

@@ -351,19 +351,15 @@ func (self *worker) wait() {
 	}
 }
 
+// push sends a new work task to currently live miner agents.
 func (self *worker) push(work *Work) {
-	if atomic.LoadInt32(&self.mining) == 1 {
-		if core.Canary(work.state) {
-			glog.Infoln("Toxicity levels rising to deadly levels. Your canary has died. You can go back or continue down the mineshaft --more--")
-			glog.Infoln("You turn back and abort mining")
-			return
-		}
-		// push new work to agents
-		for agent := range self.agents {
-			atomic.AddInt32(&self.atWork, 1)
-			if agent.Work() != nil {
-				agent.Work() <- work
-			}
+	if atomic.LoadInt32(&self.mining) != 1 {
+		return
+	}
+	for agent := range self.agents {
+		atomic.AddInt32(&self.atWork, 1)
+		if ch := agent.Work(); ch != nil {
+			ch <- work
 		}
 	}
 }