blog: correct the auditor paragraph, which was wrong against Meta (#596)

The post said the auditor's reports were confidential "with no
requirement that any of it be published." §III.J says the opposite: the
auditor shall make public an executive summary of every Final Report,
with a specified floor including whether Meta adopted its
recommendations. The full reports stay confidential under §III.G.7 and
Meta comments on the summary before release, so the qualifiers survive. …