Move `refreshAfterWrite` and `maxAge` into the breaking changes

Previously these settings were erroneously ignored for persistent caches.
Move the note into the breaking section for highlighting to the admins
that they need to analyse them carefully from v3.6.8 and v3.7.6 upon
upgrading.

Change-Id: I6f7031d4b5a9b88319cf2c4663715b14ad50b989
2 files changed