dial race where caller hangs up while dial is starting (#737)

lib/tasks/dial.js

@@ -636,6 +636,8 @@ class TaskDial extends Task {
               await this._connectSingleDial(cs, sd);
             } catch (err) {
               this.logger.info({err}, 'Dial:_attemptCalls - Error calling _connectSingleDial ');
+              sd.removeAllListeners();
+              this.kill(cs);
             }
           })
           .on('decline', () => {