Update the server to provide a basic framework for controlling when plugins
will be invoked.  There are two basic changes:

- Add a new ds-cfg-invoke-for-internal-operations configuration attribute for
  all plugins, which indicates whether the plugin should be invoked for
  internal operations.  If this is false, then the plugin will only be invoked
  for externally-requested operations.

- Add four new plugin types:  postSynchronizationAdd,
  postSynchronizationDelete, postSynchronizationModify, and
  postSynchronizationModifyDN.  These allow a plugin to perform a limited set
  of processing for changes that are successfully applied through
  synchronization.


The unique attribute plugin has also been updated to support the
post-synchronization plugin types so that if a conflict is introduced
concurrently on two different servers within the propagation delay, an
administrative alert will be generated to indicate that manual intervention is
required to address the problem.

Finally, ensure that audit logging is enabled during the unit tests, and
update the audit logger to include the connection ID and operation ID for the
operation being logged.


OpenDS Issue Number:  2057