The /archive action should return a 404 when an invalid second path param is used

[rgrove]

The /archive action supports numeric path parameters to indicate page numbers, such as /archive/2. However, if an invalid or out of range parameter, such as /archive/foo, is specified, the first archive page is returned.

This can result in dupe content in search engines. Instead of returning the first page of results, /archive/foo should return a 404.

[rgrove]

Return 404 for out of bounds archive pages. losed by 24c99a1