SOLR-5231: Fixed a bug with the behavior of BoolField that caused documents w/o a value for the field to act as if the value were true in functions if no other documents in the same index segment had a value of true.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1521948 13f79535-47bb-0310-9956-ffa450edef68