Fix bug #66721

Add NULL check to php_date_parse_tzfile's retval
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  Fix bug #66721
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  Fix bug #66721
Merge branch 'PHP-5.6'

* PHP-5.6:
  Fix bug #66721