Handle a case where document has no field 'product'. (Whoosh 2.5 compatibility)
Handle a case where document has no field 'product'. (Whoosh 2.5 compatibility)

With Whoosh 2.4 all documents have a value in field 'product'
(our workaround to keep faceting from braking). In Whoosh 2.5 this is no longer
the case so this test failed.

Refs: #741


git-svn-id: 5633281caa5e9404329cce92d0b6acb034caef48@1559082 13f79535-47bb-0310-9956-ffa450edef68

apache/bloodhound,apache/bloodhound,apache/bloodhound,apache/bloodhound