some changelog work

Changes in version 0.2.7.3-rc - 2015-09-2?

  XXXX write a blurb

  Tor 0.2.7.3-rc is the first release candidate in the 0.2.7 series.  It

  contains numerous usability fixes for Ed25519 keys, safeguards against

  several misconfiguration problems, and numerous bugfixes and small

  features.

  This is the most tested release of Tor to date. The unit tests cover

  39.40% of the code, and the integration tests (accessible with "make

  test-full", requiring stem and chutney) raise the coverage to XXX.

  If this is your first time upgrading a relay to Tor 0.2.7, your Tor

  relay will, by default, generate a new Ed25519 identity key.  If you

  would prefer to keep your Ed25519 identity key offline or encrypted

  for improved security, you can do so by following the instructions at

  XXX.

  o Major features (security, hidden services):

    - For an hidden service, it is now prohibited to use one single