factory: Use bytes with `xmlrpc.client.Binary()`

BUG=chromium:999876
TEST=None

Change-Id: Iba8e1d27df9ba81bc20d588abb66a06208c2af1e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/factory/+/1991238
Tested-by: Yilin Yang (kerker) <kerker@chromium.org>
Commit-Queue: Yilin Yang (kerker) <kerker@chromium.org>
Reviewed-by: Yong Hong <yhong@chromium.org>
diff --git a/py/gooftool/commands.py b/py/gooftool/commands.py
index 87b0253..ec04a90 100755
--- a/py/gooftool/commands.py
+++ b/py/gooftool/commands.py
@@ -632,7 +632,8 @@
   """
   report_archive = CreateReportArchive(*args, **kwargs)
   try:
-    return xmlrpc.client.Binary(file_utils.ReadFile(report_archive))
+    return xmlrpc.client.Binary(
+        file_utils.ReadFile(report_archive, encoding=None))
   finally:
     os.unlink(report_archive)