Coverity analysis defect 101249: Using invalid iterator

An invalid or past-the-end iterator is being used

Defect 101249 (STATIC_C)
Checker INVALIDATE_ITERATOR (subcategory none)
File: /src/mongo/util/options_parser/value.cpp
Function _ZNK5mongo17optionenvironment5Value8toStringB5cxx11Ev
/src/mongo/util/options_parser/value.cpp, line: 223
Function "end" creates an iterator.

                    sb << _stringMapVal.end()->first << ":" << _stringMapVal.end()->second;

/src/mongo/util/options_parser/value.cpp, line: 223
Dereferencing iterator "this->_stringMapVal.end()" though it is already past the end of its container.

                    sb << _stringMapVal.end()->first << ":" << _stringMapVal.end()->second;