message: [Net] Add additional checkpoints
  This adds two additional checkpoints for known split points
diff: @@ -69,11 +69,13 @@ static Checkpoints::MapCheckpoints mapCheckpoints =
  (908000, uint256("202708f8c289b676fceb832a079ff6b308a28608339acbf7584de533619d014d"))
  (1142400, uint256("98aff9d605bf123247f98b1e3a02567eb5799d208d78ec30fb89737b1c1f79c5"))
  (1679090, uint256("f747ce055ba1b12e1f2e842bd480bc647210799359cb2e553ab292065e3419d6")) //!< First block with a "wrapped" serial spend
  - (1686229, uint256("bb42bf1e886a7c23474634c90893dd3d68a6ccbfea4ac92a98da5cad0c6a6cb7")); //!< Last block in the "wrapped" serial attack range
  + (1686229, uint256("bb42bf1e886a7c23474634c90893dd3d68a6ccbfea4ac92a98da5cad0c6a6cb7")) //!< Last block in the "wrapped" serial attack range
  + (1778954, uint256("0d3241268264a2908d6babf00d9cd1ffb83d93d7bb4e428820127fe227c2029c")) //!< Network split here
  + (1788528, uint256("ea9243ff8fc079fdd7a04f11fac415de4d98e1bb0dc38db6f79f8f8bbfdbe496")); //!< Network split here
  static const Checkpoints::CCheckpointData data = {
  &mapCheckpoints,
  - 1551924791, // * UNIX timestamp of last checkpoint block
  - 4036872, // * total number of transactions between genesis and last checkpoint
  + 1556529343, // * UNIX timestamp of last checkpoint block
  + 4271692, // * total number of transactions between genesis and last checkpoint
  // (the tx=... number in the SetBestChain debug.log lines)
  2000 // * estimated number of transactions per day after checkpoint
  };
  