feat(alerting): make sure the map contains the responding alert

pkg/services/alerting/alerting.go

@@ -129,9 +129,11 @@ func (this *Scheduler) Executor(executor Executor) {
 func (this *Scheduler) HandleResponses() {
 	for response := range this.responseQueue {
 		log.Info("Response: alert %d returned %s", response.id, response.state)
+		if this.jobs[response.id] != nil {
 			this.jobs[response.id].running = false
 		}
 	}
+}
 
 func (this *Scheduler) Measure(exec Executor, rule *AlertJob) {
 	now := time.Now()