added "IDN" to ReferenceAggregateManager._my_urn
added "IDN" to ReferenceAggregateManager._my_urn

The ReferenceAggregateManager was presenting an illegal URN:
"urn:publicid:geni:gpo:gcf+authority+am"
instead of
"urn:publicid:IDN+geni:gpo:gcf+authority+am"
This was due to the lack of the "IDN" parameter on the publicid_to_urn method call.
tcmitchell/geni-tools,tcmitchell/geni-tools