Fixed reported crash on handling encode failure.

Author: RandomEngy

VidCoder/Services/HandBrakeProxy/RemoteScanProxy.cs

@@ -18,6 +18,7 @@ public class RemoteScanProxy : RemoteProxyBase<IHandBrakeScanWorker, IHandBrakeS
     public async void StartScan(string path, IAppLogger logger)
 	{
 		this.Logger = logger;
+		this.result = null;
 
 		await this.RunOperationAsync(worker => worker.StartScan(path));
 	}

VidCoder/Services/QueueAdderService.cs

@@ -178,7 +178,7 @@ private void EnsureScanProxyCreated()
 
 					if (!scanFoundTitle)
 					{
-						this.ScanFailed.Invoke(this, new EventArgs<string>(this.currentScan.SourcePath.Path));
+						this.ScanFailed?.Invoke(this, new EventArgs<string>(this.currentScan.SourcePath.Path));
 					}
 
 					this.scansCompletedThisSession++;