Fix for https://github.com/dotCMS/dotCMS/issues/3171

Fix for https://github.com/dotCMS/dotCMS/issues/3171 - When you used a file in you structure, but it wasn't required. You couldn't use this function for creating a contentlet without file. The problem was parametersName.add(tempBinaryValues.get("parameterName").toString());. When there isn't a file, the parametersName.add(tempBinaryValues.get("parameterName") returns null. But the line will do a .toString() without any checks. So this will give a NullPointerException. 

Thanks,
Danny Gloudemans
ISAAC