fix download cut

Assets/SibylSystem/ResourceManagers/HttpDldFile.cs

@@ -19,7 +19,10 @@ public class HttpDldFile
             {
                 Directory.CreateDirectory(Path.GetDirectoryName(filename));
             }
-
+            if (File.Exists(filename + ".tmp"))
+            {
+                File.Delete(filename + ".tmp");
+            }
             using (var client = new TimeoutWebClient())
             {
                 ServicePointManager.ServerCertificateValidationCallback = MyRemoteCertificateValidationCallback;