Attempt to reinstate 'expert help' functionality

This commit originally added this stuff:
d4073b5

This commit seems to have removed it:
ee5ea6e

app/controllers/catalog_controller.rb

@@ -173,11 +173,7 @@ def self.generate_cluster_fq(index, limit, elvl = false)
         'facet.mincount': 0,
         #      fq: '{!tag=cluster}{!collapse field=cluster_id nullPolicy=expand size=5000000 min=record_source_id}',
         # this approach needs expand.field=cluster_id
-<<<<<<< HEAD
         # MOVE TO FACET: fq: '{!bool tag=cluster must_not=$x1 must_not=$x2 must_not=$x3 must_not=$x4 must_not=$x5 must_not=$x6 must_not=$x7}',
-=======
-        fq: %q~{!tag=cluster}NOT ({!join from=cluster_id to=cluster_id v='record_source_f:"Penn"'} AND record_source_f:"HathiTrust") NOT record_source_id:3~,
->>>>>>> 4618572... temporarily add links to hathi records corresponding to local holdings
         expand: 'true',
         'expand.field': 'cluster_id',
         'expand.q': '*:*',