Fix an issue where s3 might return dupilcate folders
Fix an issue where s3 might return dupilcate folders

chrisseto/waterbutler,felliott/waterbutler,hmoco/waterbutler,cosenal/waterbutler,rafaeldelucena/waterbutler,Ghalko/waterbutler,CenterForOpenScience/waterbutler,kwierman/waterbutler,RCOSDP/waterbutler,rdhyee/waterbutler,icereval/waterbutler,Johnetordoff/waterbutler,TomBaxter/waterbutler