Fix malformed geni_credential_types output from tmcd
Report by Nick Bastin:
The problematic field on my current example is "geni_credential_types" within getversion, whose value is a malformed JSON object: "geni_credential_types":{{"geni_type":"geni_sfa","geni_version":"2"},{"geni_type":"geni_sfa","geni_version":"3"}}