This reverts commit 3fa7d3c8.

Some portions of the test suite did not correctly handle asyncmeta, fix
those issues.  Tests execute and pass after this change

Some additional fixes for the testsuite now that back-bdb/hdb are no
longer present.

This commits deletes all references and code for back-bdb and back-hdb.
There is some follow up work still necessary to flush out the admin
guide for back-mdb.

Essentially reverts part of cd8ff376 to
make sure there is always a contextCSN if the server is in charge of its
own serverID.

Was omitted from dda779d8

Sumit Bose authored May 07, 2013 and Howard Chu committed Apr 18, 2019

Was using the ldapi socket path as a hostname

Update to note that MDB is the primary backend and HDB/BDB are
deprecated.

Commit 279594c2 officially marked
slapd-mdb as being the recommended backend for OpenLDAP, superseding
back-hdb.  This man page was missed during that update.

Comment in the code referenced Referential Integrity overlay instead of
the Return Code overlay.

Kris Zyp authored Apr 15, 2019 and Howard Chu committed Apr 16, 2019

Broken in ITS#8756

Follow on to commit 88d22a1c

Remove dead code

Nadezhda Ivanova authored Feb 28, 2019 and Quanah Gibson-Mount committed Feb 28, 2019

On error, the ldap connection was freed and under some circumstances the fd was being reused,
which caused an assertion error in connection_init.

Nadezhda Ivanova authored Feb 07, 2019 and Quanah Gibson-Mount committed Feb 28, 2019

This option instructs try_read1msg to not free the connection on read error
or on Notice of disconnections, but leave it to the caller. It is needed,
for example, by back-asyncmeta, who expects to have control on when
its target connections are freed. Must be used with caution.

Nadezhda Ivanova authored Feb 18, 2019 and Quanah Gibson-Mount committed Feb 28, 2019

Includes all the changes necessary to fix back-asyncmeta issues
discovered during on-site testing since the start of 2016.
These include:
Issues with stability - crashes and assetion failures
Incorrect behavior during unstable network conditions, such as inability to reset connections
or process responses, or "hanging" to wait for a response that would never be received.
Memory leaks and memory management fixes - major redesign of the way back-asyncmeta
works with memory contexts.
Rewrite was replaced with suffix-massage in configuration, and the network-timeout value was changed to milliseconds.
Incorrect behavior when SASL is used to bind to a target.
Many problems caused by race conditions
Fixes for compiler warnings, and tests.
Cleanup of unused code.