Support more fields of GetVersion.
Support more fields of GetVersion.

Add geni_api_versions and geni_credential_types which are both required
in AM API v3.

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