(ITS#8493) Under heavy modrdn load, masters desync

[quanah@openldap.org]

Full_Name: Quanah Gibson-Mount
Version: 2.4.44+ITS8432
OS: Linux 2.6
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (75.111.52.177)


Trying to reproduce another ITS, I discovered a new bug.  When doing MODRDN ops
on one master, the other master keeps going out of sync. Specifically:

Sep  3 01:12:17 zre-ldap002 slapd[29206]: syncrepl_message_to_op: rid=100
be_modrdn uid=user.924,ou=people,dc=zre-ldap002,dc=eng,dc=zimbra,dc=com (32)
Sep  3 01:12:17 zre-ldap002 slapd[29206]: do_syncrep2: rid=100 delta-sync lost
sync on (reqStart=20160903051215.747829Z,cn=accesslog), switching to REFRESH