Ruby

• ext/psych/parser.c (parse): fix assertion error when reusing a
  parser after an exception has been raised
• test/psych/test_parser.rb: test for assertion error

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@30625 b2dd03c8-39d4-4d8f-98ff-823fe69b080e