In our cloud environments, we're observing a weird issue where
this function is returning `None` for systems that are already
running and exist.
Due to the fact that it returns `None` right away, we don't
actually get a reason as to why the request failed and it is
returning a 404.
This should not clobber up the logs much more, due to the fact
that if you are sending a request to the metadata service, you're
supposed to already exist, so not being able to find the metadata
for an instance seems like a broken case.
This patch should help operators at least uncover why exactly
their instances are failing to get the metadata to further
troubleshoot.
Change-Id: Iadca69fee24ec89408f9fca68d1da46c918577bc
7320817799