generator.h: use GET_STATE_TO

* ext/json/generator/generator.h (GENERATE_JSON): use GET_STATE_TO
  macro, instead of TypedData_Get_Struct directly.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49048 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-12-29

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49049 b2dd03c8-39d4-4d8f-98ff-823fe69b080e