Allow access to 7999/tcp on cache boxes
Allow access to 7999/tcp on cache boxes

- A new cache-clearing on (re-)publishing mechanism requires backend
  machines to access 7999.

- More fine-grained access limits are defined in the vCloud VDC edge
  rules (Allow access to router 7999 by backend.

solo: da39a3ee5e6b4b0d3255bfef95601890afd80709@schmie

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet