message: [RPC] Fix verifychain
  verifychain only accepts a single (optional) argument instead of two,
  and we need to capture that argument properly.
diff: @@ -546,7 +546,7 @@ UniValue gettxout(const UniValue& params, bool fHelp)
  UniValue verifychain(const UniValue& params, bool fHelp)
  {
  - if (fHelp || params.size() > 2)
  + if (fHelp || params.size() > 1)
  throw runtime_error(
  "verifychain ( numblocks )\n"
  "\nVerifies blockchain database.\n"
  @@ -565,7 +565,7 @@ UniValue verifychain(const UniValue& params, bool fHelp)
  int nCheckLevel = 4;
  int nCheckDepth = GetArg("-checkblocks", 288);
  if (params.size() > 0)
  - nCheckDepth = params[1].get_int();
  + nCheckDepth = params[0].get_int();
  fVerifyingBlocks = true;
  bool fVerified = CVerifyDB().VerifyDB(pcoinsTip, nCheckLevel, nCheckDepth);
  