net/http/header.rb: remove a hack

* lib/net/http/header.rb (Net::HTTPHeader#set_range): remove a hack
  for the bug fixed at [Bug #8739].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42403 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
json/add/range.rb: use Range#end

* ext/json/lib/json/add/range.rb (Range#as_json): use Range#end
  instead of Range#last which can be affected by Range#exclusive?.
  ref [Bug #8739]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42404 b2dd03c8-39d4-4d8f-98ff-823fe69b080e