This change formats internal Fluent logs in a similar way to other
logs. It makes it easier for a user to identify issues with Fluent
parsing logs. Any failure to parse a log will be ingested into the
logging framework and can easily be located by searching for
'pattern not match' or by filtering for Fluent log warnings.
Change-Id: Iea6d12c07a2f4152f2038d3de2ef589479b3332b
d89a89c26b