removed 's3' default key value in generate_ontology argparser
removed 's3' default key value in generate_ontology argparser

4dn-dcic/fourfront,hms-dbmi/fourfront,4dn-dcic/fourfront,hms-dbmi/fourfront,4dn-dcic/fourfront,hms-dbmi/fourfront,hms-dbmi/fourfront,4dn-dcic/fourfront,hms-dbmi/fourfront