check for null in case where deleteAllMessages is called w/o broker ref, prevelant in tests resulting in bogus errors

activemq-jdbc-store/src/main/java/org/apache/activemq/store/jdbc/TransactionContext.java

@@ -69,7 +69,9 @@ public class TransactionContext {
                 inTx = false;
                 close();
                 IOException ioe = IOExceptionSupport.create(e);
+                if (persistenceAdapter.getBrokerService() != null) {
                     persistenceAdapter.getBrokerService().handleIOException(ioe);
+                }
                 throw ioe;
             }