message: Fix -Wmissing-field-initializers warnings in gcc 4.9
  The previous method of initialisation was correct for c++11
  but GCC 4.9 gives false positives about it.
  For more information see:
diff: @@ -46,7 +46,7 @@ Timestamp from_timestamp_values(std::vector<std::string> const& time_inputs) {
  }
  else if (time_inputs.size() == 6 || time_inputs.size() == 7) {
  // readable format YYYY-MM-DD-HH:MM:SS:NANOS nanos optional
  - tm created{};
  + struct tm created = tm();
  created.tm_year = stot<int>(time_inputs[0]) - 1900; // epoch offset (see man mktime)
  created.tm_mon = stot<int>(time_inputs[1]) - 1; // converts from 1-12 to 0-11
  created.tm_mday = stot<int>(time_inputs[2]);
  