OPENJPA-1616 add comment

git-svn-id: https://svn.apache.org/repos/asf/openjpa/trunk@932027 13f79535-47bb-0310-9956-ffa450edef68

openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java

@@ -426,6 +426,7 @@ public class MySQLDictionary
     @Override
     protected int matchErrorState(Map<Integer,Set<String>> errorStates, SQLException ex) {
         int state = super.matchErrorState(errorStates, ex);
+        // OPENJPA-1616 - Special case for MySQL not returning a SQLState for timeouts
         if (state == StoreException.GENERAL && ex.getErrorCode() == 0 && ex.getSQLState() == null) {
             // look at the nested MySQL exception for more details
             SQLException sqle = ex.getNextException();