makes autoclient delete old data files

Tools/AutoClient/Purchaser.cs

@@ -84,15 +84,34 @@ namespace AutoClient
         private async Task<string> StartNewPurchase()
         {
             var file = await CreateFile();
+            try
+            {
                 var cid = await UploadFile(file);
                 return await RequestStorage(cid);
             }
+            finally
+            {
+                DeleteFile(file);
+            }
+        }
 
         private async Task<string> CreateFile()
         {
             return await app.Generator.Generate();
         }
 
+        private void DeleteFile(string file)
+        {
+            try
+            {
+                File.Delete(file);
+            }
+            catch (Exception exc)
+            {
+                app.Log.Error($"Failed to delete file '{file}': {exc}");
+            }
+        }
+
         private async Task<ContentId> UploadFile(string filename)
         {
             using var fileStream = File.OpenRead(filename);