add omitTf to StringFieldable for newer lucene versions (back compatible with current lucene and makes testing with lucene trunk possibe)

git-svn-id: https://svn.apache.org/repos/asf/lucene/solr/trunk@684581 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/solr/handler/component/QueryComponent.java

@@ -786,6 +786,13 @@ public class QueryComponent extends SearchComponent
     public void setOmitNorms(boolean omitNorms) {
     }
 
+    public void setOmitTf(boolean omitTf) {
+    }
+
+    public boolean getOmitTf() {
+      return false;
+    }
+
     public boolean isLazy() {
       return false;
     }