Fixes #4441 - Overriden link_to method breaks conventional use as provid...

...ed

by action_view/helpers/url_helper.rb by being placed as a protected helper method.

The base 'link_to' function in Rails action_view is exposed a public method
available to helpers. Commit bfee97b6a6980b6ad4f5bd65f4b60680f08967f5 overrides
the Rails 'link_to' function and hides it as a protected method thereby breaking
the expected use pattern of 'link_to'.