How to resolve error on conflicting API response

[jbusecke]

As encountered in here and confirmed in #190, there seems to be an issue with at least one of the GISS models, where the client cannot reconcile the API response from different nodes.

I need to do the following:

• Narrow down the exact dataset(s) this happens to
  • Report to ESGF
• Handle the error better internally. The easiest would just to ignore the entry but not fail out, but maybe I can use some of the above insight to decide on one of the records. TBD