Fixed bugs with page sweeper.
Fixed bugs with page sweeper.

In particular:
  * Fixed bug where `page_cache_directory = Pathname.new(page_cache_directory.to_s)` returns an empty path.
  * Changed `cache_root.rmdir` to `FileUtils.rm_rf cache_root` in order to delete an non-empty directory.
  * Remove the `pages.html` file that is outside the `../pages/` directory and any file like it (for example pages.html.gz)

refinery/refinerycms,anitagraham/refinerycms,trevornez/refinerycms,louim/refinerycms,mabras/refinerycms,bricesanchez/refinerycms,kelkoo-services/refinerycms,anitagraham/refinerycms,hoopla-software/refinerycms,kelkoo-services/refinerycms,Eric-Guo/refinerycms,mobilityhouse/refinerycms,simi/refinerycms,Retimont/refinerycms,johanb/refinerycms,stefanspicer/refinerycms,refinery/refinerycms,bryanmtl/g-refinerycms,sideci-sample/sideci-sample-refinerycms,stefanspicer/refinerycms,LytayTOUCH/refinerycms,gwagener/refinerycms,mkaplan9/refinerycms,mlinfoot/refinerycms,mojarra/myrefinerycms,KingLemuel/refinerycms,gwagener/refinerycms,aguzubiaga/refinerycms,mkaplan9/refinerycms,stefanspicer/refinerycms,bricesanchez/refinerycms,KingLemuel/refinerycms,louim/refinerycms,trevornez/refinerycms,simi/refinerycms,chrise86/refinerycms,mojarra/myrefinerycms,kappiah/refinerycms,kappiah/refinerycms,gwagener/refinerycms,johanb/refinerycms,chrise86/refinerycms,mobilityhouse/refinerycms,mlinfoot/refinerycms,mabras/refinerycms,hoopla-software/refinerycms,kappiah/refinerycms,simi/refinerycms,Eric-Guo/refinerycms,mabras/refinerycms,johanb/refinerycms,KingLemuel/refinerycms,hoopla-software/refinerycms,aguzubiaga/refinerycms,mkaplan9/refinerycms,simi/refinerycms,mlinfoot/refinerycms,LytayTOUCH/refinerycms,trevornez/refinerycms,Retimont/refinerycms,Retimont/refinerycms,LytayTOUCH/refinerycms,refinery/refinerycms,chrise86/refinerycms,bryanmtl/g-refinerycms,anitagraham/refinerycms,Eric-Guo/refinerycms,aguzubiaga/refinerycms,sideci-sample/sideci-sample-refinerycms