Update logic for S3 metadata listing
Update logic for S3 metadata listing

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