Do not worry about versioning on OPTIONS requests

- CORS preflight requests from browsers often (typically?) do not pass
  Accept headers, or, if they do, use "*/*", losing the versioned
  mediatype. By omitting the version check/change during OPTIONS
  requests, we can make this continue to work.
Merge branch 'hotfix/options-cors'

Omit version-munging on OPTIONS requests in order to prevent false-404s on CORS
preflights.