Merge branch '2.3.x'

* 2.3.x:
  (#12357) Fix broken compatibility with Puppet 2.6
  (maint) Comment Ken's fix to String#any?
  (#13018) Fix missing method any? message for ruby 1.9.x
  (#12357) Add ability to display an error message from validate_re
  (#12357) Add validate_absolute_path() function
  (maint) Stop printing the directory of spec_helper
  (#12357) Make facter_dot_d look in Puppet[:confdir]/facts.d
  (#12357) Add puppet_vardir custom fact
  (#12357) Fix root_home fact on Windows