Remove unnecessary gsub call.
Originally this gsub call appeared as "for performance" hack. But unfortunattely having it right there doesn't fix some problems described here: 8317cde
Now, we can remove it.
Also removed test that asserts some internal behavior of the formatter that doesn't have a use case in actionpack: it tests behavior of formatter when it doens't have all required parameters, but this case is filtered at verify_required_parts!.
Route formatter: remove unnecessary gsub call