DERBy-6157; text for message XSLA4 might encouraging people to delete part of the transaction log.
  backport of revision 1469552 from 10.9 branch


git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/branches/10.8@1471161 13f79535-47bb-0310-9956-ffa450edef68