merge revision(s) 55497,55498,55504: [Backport #11988]
* ext/psych/*, test/psych/*: Upate psych 2.1.0 This version fixed [Bug #11988][ruby-core:72850] * ext/psych/*, test/psych/*: Update psych 2.1.0
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@55902 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 55497,55498,55504: [Backport #11988]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@55902 b2dd03c8-39d4-4d8f-98ff-823fe69b080e