message: Prepare changelog for v0.8.6
diff: +Changes in [0.8.6](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.8.6) (2017-02-04)
  +===================================================================================================
  +[Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.8.6-rc.3...v0.8.6)
  +
  + * Update to matrix-js-sdk 0.7.5 (no changes from 0.7.5-rc.3)
  +
  Changes in [0.8.6-rc.3](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.8.6-rc.3) (2017-02-03)
  =============================================================================================================
  [Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.8.6-rc.2...v0.8.6-rc.3)
  + * Update to matrix-js-sdk 0.7.5-rc.3
  * Fix deviceverifybuttons
  [5fd7410](https://github.com/matrix-org/matrix-react-sdk/commit/827b5a6811ac6b9d1f9a3002a94f9f6ac3f1d49c)
  