Fix for ALF-10561 SOLR stops indexing if it is given a property that is neither indexed or stored - it throws an exception

Fix ALF-10358 	SOLR No easy way to get the current last TX indexed to monitor how the SOLR index is building

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@30857 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/solr/SOLRTrackingComponent.java

@@ -142,4 +142,10 @@ public interface SOLRTrackingComponent
      * @param enabled
      */
     void setEnabled(boolean enabled);
+    
+    /**
+     * Get the last transaction timestamp from the repo
+     * @return
+     */
+    public Long getMaxTxnCommitTime();
 }