using lmdb the changelog is wrongly recreated by reindex task.

[progier389]

Issue Description
freeipa test case fails because replicationis broken (missing csn in changelog), and error logs shows that changelog get recreated after a reindex task.

Freeipa ipatests.test_integration.test_simple_replication.TestSimpleReplication test fails in freeipa-pr-ci2/freeipa#3326

The replica error logs shows:

[23/Jan/2024:08:16:27.387781400 +0000] - DEBUG - NSMMReplicationPlugin - replay_update - agmt="cn=meTomaster.ipa.test" (master:389): Sending modify operation (dn="cn=master.ipa.test-to-replica0.ipa.test,cn=domain,cn=topology,cn=ipa,cn=etc,dc=ipa,dc=test" csn=65af75da000200030000)
...
                                                                     
[23/Jan/2024:08:16:28.261824676 +0000] - INFO - dbmdb_db2index - userRoot: Indexing attribute: ipaidpconfiglink
...
[23/Jan/2024:08:16:28.572130451 +0000] - INFO - dbmdb_public_dbmdb_import_main - reindex userRoot: Reindexing complete.  Processed 554 entries in 1 seconds. (554.00 entries/sec)

...

[23/Jan/2024:08:16:28.579981020 +0000] - DEBUG - NSMMReplicationPlugin - replica_reload_ruv - changelog contains changes that are not in the databae.
[23/Jan/2024:08:16:28.580384608 +0000] - WARN - NSMMReplicationPlugin - replica_reload_ruv - New data for replica dc=ipa,dc=test does not match the data in the changelog.
 Recreating the changelog file. This could affect replication with replica's consumers in which case the consumers should be reinitialized.

...

[23/Jan/2024:08:16:29.776478091 +0000] - ERR - agmt="cn=meTomaster.ipa.test" (master:389) - clcache_load_buffer - Can't locate CSN 65af75da000200030000 in the changelog (DB rc=-12797). If replication stops, the consumer may need to be reinitialized.

==> Looks like the RUV was not properly written in the db when the backend got disabled by the reindex task so the changelog get discarded when backend is reenabled after the reindex

Package Version and Platform:

• Platform: Fedora
• Package and version: 389-ds-base-3.0.0

Steps to Reproduce
Steps to reproduce the behavior:

1. run freeipa tests.
2. See test result: 389ds-fedora/simple_replication fails
3. freeipa test_simple_replication

Expected results

1. freeipa **389ds-fedora/simple_replication ** should pass
2. changelog should never be recreated after a reindex.

Additional context
Add any other context about the problem here.

[progier389]

Error logs comfirm my guess:
So in memory RUV is same than the changelog i.e: 65af75da000200030000
But database RUV is not up to date 65af75d0000000030000
For some reason in memory RUV was not written into the database when the backend state changed.

[23/Jan/2024:08:16:28.579658527 +0000] - DEBUG - NSMMReplicationPlugin - replica_reload_ruv changelog RUV: {replica 3} 65af74d7000000030000 65af75da000200030000 65af75da
...
[23/Jan/2024:08:16:28.218333980 +0000] - DEBUG - NSMMReplicationPlugin - create_ReplicationExtopPayload: {replica 3 ldap://replica0.ipa.test:389} 65af74d7000000030000 65af75da000200030000 65af75da
...
[23/Jan/2024:08:16:28.577876672 +0000] - DEBUG - NSMMReplicationPlugin - replica_reload_ruv database RUV: {replica 3 ldap://replica0.ipa.test:389} 65af74d7000000030000 65af75d0000000030000 00000000

[progier389]

Apparently the problem is not that the RUV is not written (because the backend is not disabled but put in read only and busy mode) that is because it is reenabled at the end of the reindex (in reindex case it should be set back in non busy mode instead of being reenabled.)