Scalability reform part 3 (content-repository):
- content_revision__del:
* Removed manual nulling of live_revision and latest_revision
by using appropriate ond delete actions on foreign keys
* Removed manual deletion of old_revision and new_revision in
cr_item_publish_audit by using "on delete cascade"
- content_item__del:
* Removed manual deletion of item_id in cr_item_publish_audit
by using "on delete cascade"
* Removed manual deletion of item_id in cr_release_periods
by using "on delete cascade"
* Removed manual deletion of item_id in cr_item_template_map
by using "on delete cascade"
* Removed manual deletion of item_id in cr_item_keyword_map
by using "on delete cascade"
* Removed manual deletion of direct permissions (was already
cascading)
- Added missing index for child_id to cr_child_rels.
This index was in the create scripts (with a non-conformant name),
but not in the upgrade scripts
- bump version number of acs-content-repository to 5.9.0d3
