Beware! This is an incompatible change. The new connector has no support
for "old" object classes (AccountObjectClass, GroupObjectClass) and uses
a different name for "plain" groups (ri:CustomPlainGroupObjectClass ->
ri:Group). Also the name and uid attribute names has been changed to
ri:name and ri:uuid.
Obsolete midpoint-objects directory was renamed appropriately before
it's definitely deleted.