DERBY-1458; modified check for missing/orphaned messages to only run the junit   task if the optional ant junit package is available
DERBY-1458; modified check for missing/orphaned messages to only run the junit
  task if the optional ant junit package is available


git-svn-id: 2c06e9c5008124d912b69f0b82df29d4867c0ce2@705252 13f79535-47bb-0310-9956-ffa450edef68

trejkaz/derby,apache/derby,trejkaz/derby,apache/derby,apache/derby,apache/derby,trejkaz/derby