Remove unused code.

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1557870 13f79535-47bb-0310-9956-ffa450edef68
Don't automatically add the default field; instead, rely on the
Lucene or Solr query to handle default field.
Set the default field in the Solr query.
Add test cases for default field.

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1558035 13f79535-47bb-0310-9956-ffa450edef68