Make sure that responses with any of private, no-cache, no-store are never cached

Previously, if a response was sent with:

	Cache-Control: private, max-age=300

Varnish would still cache this object for 5 minutes.

Change-Id: Ie64400bd1a8f64dc9d69b5c9588a1b01ccaa8fe0
Merge "Make sure that responses with any of private, no-cache, no-store are never cached" into production