clarify instruction for finding AM URN in a cert
clarify instruction for finding AM URN in a cert

tcmitchell/geni-tools,GENI-NSF/gram,plantigrade/geni-tools,ahelsing/geni-tools,ahelsing/geni-tools,GENI-NSF/gram,tcmitchell/geni-tools,plantigrade/geni-tools,GENI-NSF/gram