message: wallet: refactor: inline function ReadOrderPos()
  Since accounts were removed in commit
  this function is only called at one place and thus can be as well inlined. Also,
  avoid a duplicate lookup by using the find() method and dereference, instead of
  calling count() and operator[].
diff: typedef std::map<std::string, std::string> mapValue_t;
  -static inline void ReadOrderPos(int64_t& nOrderPos, mapValue_t& mapValue)
  -{
  - if (!mapValue.count("n"))
  - {
  - nOrderPos = -1; // TODO: calculate elsewhere
  - return;
  - }
  - nOrderPos = atoi64(mapValue["n"]);
  -}
  -
  -
  static inline void WriteOrderPos(const int64_t& nOrderPos, mapValue_t& mapValue)
  {
  if (nOrderPos == -1)
  @@ -232,7 +221,8 @@ public:
  setConfirmed();
  }
  - ReadOrderPos(nOrderPos, mapValue);
  + const auto it_op = mapValue.find("n");
  + nOrderPos = (it_op != mapValue.end()) ? atoi64(it_op->second) : -1;
  nTimeSmart = mapValue.count("timesmart") ? (unsigned int)atoi64(mapValue["timesmart"]) : 0;
  mapValue.erase("fromaccount");
  