A book for which the library owns no licenses will be indexed in Elasticsearch as available=false, which is what we were using to find books that are "not currently available". But a book like that isn't available at all and it won't ever show up in an OPDS feed.
To find books that are not currently available we need to check both available=false and licensed=true.
This branch fixes a bug I found while doing QA on https://jira.nypl.org/browse/SIMPLY-3236.
A book for which the library owns no licenses will be indexed in Elasticsearch as available=false, which is what we were using to find books that are "not currently available". But a book like that isn't available at all and it won't ever show up in an OPDS feed.
To find books that are not currently available we need to check both available=false and licensed=true.