Ruby » Ruby master

• string.c (rb_str_upto): make next object before yield its block.
  fix: can modify original begin string of String#upto.
  [ruby-dev:26384] [ruby-dev:39626] #2327

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@25632 b2dd03c8-39d4-4d8f-98ff-823fe69b080e