Clean up logic for validate_path in Box
Clean up logic for validate_path in Box

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