Facets with incomplete data

[spacemansteve]

Facet generation code typically processes multi-token strings. For example, grant agency and grant number are in a single string separated by a space. Currently the code generates an exception if there is no space. It should not.

For invalid strings, the code should simply 'continue' with the next string in the loop (ignoring the current string).

https://github.com/adsabs/ADSMasterPipeline/blob/master/adsmp/solr_updater.py#L27
https://github.com/adsabs/ADSMasterPipeline/blob/master/adsmp/solr_updater.py#L36
https://github.com/adsabs/ADSMasterPipeline/blob/master/adsmp/solr_updater.py#L36