message: [RPC] Fix spork command input length
  Sporks are uint64, but the input variable was being parsed as an int,
  causing an out-of-range error for larger values.
diff: @@ -290,7 +290,7 @@ UniValue spork(const UniValue& params, bool fHelp)
  }
  // SPORK VALUE
  - int64_t nValue = params[1].get_int();
  + int64_t nValue = params[1].get_int64();
  //broadcast new spork
  if (sporkManager.UpdateSpork(nSporkID, nValue)) {
  