Revert "Merge pull request #10158 from steveklabnik/issue_10125"

This reverts commit fa3ef8e82ab2f96cf15ef9bc885b2468fad77621, reversing
changes made to e0af93dd3a5eeee2e2a67b05f34afb66cc80c00b.

Reason: Routes, Active Record and the rendering stack should not depend
on the default locale