Turn off caching in the cache controller

CacheController doesn't implement the methods needed for the caching inside
`render_content`, so turn it off while we're generating offline caches.
Move masthead content fetches into helpers

This isn't ideal, but it makes them available no matter which controller
we come in through.
remove redundant/generic OG tags from new document header
Fix two specs

* Controller spec for feeds#all_news was failing because it rejects content
  without a category, but the factory wasn't putting categories on the
  generated content
* application_helper#sphinx category searches: When I took the
  `.map(&:to_article)` off of `latest_news`, we started getting a non-array
  object, which failed the equivalence test.
conditional fallback for views without article-specific OG metadata
Merge branch 'master' of github.com:SCPR/SCPRv4
bump cache
account for Issues OpenGraph metadata
Move specs for a few functions that are now helpers
Ignore category in ContentBase comparison

We're generating a category object, and that was throwing off the array
comparison with `ContentBase.search` and `@generated_content`
Remove missed_it_bucket spec for content expiration

With ContentStore removed, this no longer works.

(@sdillingham: sorry to step on your commit from daa572c8bd3)
Update opengraph renders for caching

Since we're caching `render_content` partials now, we need to move the
opengraph `content_for` outside the cached block.
Merge branch 'master' into short-list-modules