boolean values cannot be searched with expected queries, closes #327.

modules/elasticsearch/src/main/java/org/elasticsearch/index/mapper/xcontent/XContentBooleanFieldMapper.java

@@ -116,6 +116,10 @@ public class XContentBooleanFieldMapper extends XContentFieldMapper<Boolean> {
         this.nullValue = nullValue;
     }
 
+    @Override public boolean useFieldQueryWithQueryString() {
+        return true;
+    }
+
     @Override public Boolean value(Fieldable field) {
         return field.stringValue().charAt(0) == 'T' ? Boolean.TRUE : Boolean.FALSE;
     }