I found some errors while manually testing service account impersonation on Azure. This PR includes the fixes that I made.
Change-Id: Ia2b194be6c9a7c843e615f9789c8f8203bcbc151
GitHub-Last-Rev: 5690716363
GitHub-Pull-Request: golang/oauth2#475
Reviewed-on: https://go-review.googlesource.com/c/oauth2/+/291209
Reviewed-by: Cody Oss <codyoss@google.com>
Trust: Cody Oss <codyoss@google.com>
Trust: Tyler Bui-Palsulich <tbp@google.com>
Run-TryBot: Cody Oss <codyoss@google.com>
TryBot-Result: Go Bot <gobot@golang.org>