Remove redundant use of `to_s` in interpolation
Remove redundant use of `to_s` in interpolation

Per http://www.refactorcop.com/refinery/refinerycms
trevornez/refinerycms,gwagener/refinerycms,stefanspicer/refinerycms,mlinfoot/refinerycms,anitagraham/refinerycms,trevornez/refinerycms,mabras/refinerycms,Retimont/refinerycms,johanb/refinerycms,mkaplan9/refinerycms,mabras/refinerycms,hoopla-software/refinerycms,bricesanchez/refinerycms,simi/refinerycms,KingLemuel/refinerycms,Retimont/refinerycms,KingLemuel/refinerycms,simi/refinerycms,mkaplan9/refinerycms,LytayTOUCH/refinerycms,LytayTOUCH/refinerycms,Retimont/refinerycms,johanb/refinerycms,hoopla-software/refinerycms,sideci-sample/sideci-sample-refinerycms,anitagraham/refinerycms,kappiah/refinerycms,LytayTOUCH/refinerycms,KingLemuel/refinerycms,simi/refinerycms,mlinfoot/refinerycms,bricesanchez/refinerycms,simi/refinerycms,sideci-sample/sideci-sample-refinerycms,stefanspicer/refinerycms,Eric-Guo/refinerycms,aguzubiaga/refinerycms,kappiah/refinerycms,stefanspicer/refinerycms,kappiah/refinerycms,refinery/refinerycms,aguzubiaga/refinerycms,Eric-Guo/refinerycms,mabras/refinerycms,refinery/refinerycms,anitagraham/refinerycms,trevornez/refinerycms,aguzubiaga/refinerycms,johanb/refinerycms,hoopla-software/refinerycms,gwagener/refinerycms,chrise86/refinerycms,Eric-Guo/refinerycms,gwagener/refinerycms,refinery/refinerycms,chrise86/refinerycms,mkaplan9/refinerycms,chrise86/refinerycms,mlinfoot/refinerycms