(ITS#5282) refreshAndPersist can miss changes if error occurs

[quanah@zimbra.com]

Full_Name: Quanah Gibson-Mount
Version: 2.3.39
OS: 
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (76.21.80.71)


If one is using refreshAndPersist with syncrepl, and an error occurs during a
change, the contextCSN will not be updated.  However, if a /new/ change comes in
after that, that is successful, the CSN will be updated, and the missed change
is lost.  This can happen, for example, if the replica runs out of locks while
making the change.  It would be best then, if this happens, for the replica to
drop out of persist mode.  This is a good reason to set an interval with this
mode.