Log Message:
Update to 2.24

Upstream changes:
2.24      2017-04-17 16:12:00+12:00 Pacific/Auckland
  - fix typo in last commit with mistakenly removed some underscores
  - don't initialise $XML::Simple::PREFERRED_PARSER to undef as a caller may
    have already set it before loading XML::Simple and if not, it would have
    defaulted to undef anyway (RT#118205 from Slaven Rezi�)

2.23      2017-04-17 15:49:14+12:00 Pacific/Auckland
  - another fix to the logic for detecting circular references (RT#114120 from
    Matthias Pitzl, also report from Erland Sommarskog)