Primary (and associated) memberships are not renewed when non-primary contact renews the membership

If a contact renews an inherited membership via online contribution page (i.e. they are not the primary member) - the primary membership and all inherited memberships should be renewed. Currently only the membership belonging to the contact who is doing the renewal is actually updated.

To recreate:
1. Create an inheritable membership 1 year rolling term (e.g. Household Membership -> inherited by Household Member is).
2. Create a Household and add your logged in user's contact as a Household member of that household.
3. Add an expired Household membership to the household (via backoffice 'Add Membership' - set Join Date to 12/1/2011).
4. Add Household Membership as an option in the sample online contribution page id=2 (Membership Settings)
5. Navigate to online contribution page id=2 (you will see notice about the expiration date of "your" Household Membership. Do the renewal.
6. Check membership end date / status for the membership under your contact's tab and compare to end-date / status for the primary membership under the Household contact. "Your" inherited membership is renewed while the primary Household membership is still expired.

NOTE: A related bug in the workflow where the contact owning the inherited membership renews via the primary member's "Dashboard - Membership => Renew" link was fixed previously by this issue:

http://issues.civicrm.org/jira/browse/CRM-13333

---- Original Post ----
Whenever a contact renews a membership that they are not the primary on, it renews the non-primary, but does not sync with the primary:
http://drupal.demo.civicrm.org/civicrm/contact/view/membership?action=view&reset=1&cid=203&id=33&context=membership&selectedChild=member
and
http://drupal.demo.civicrm.org/civicrm/contact/view/membership?action=view&reset=1&cid=213&id=32&context=membership&selectedChild=member

(Notice the expiration dates)

This creates a mismatch when a user renews. Their household is not renewed, nor are the other members of the household. The membership is no longer in sync.

Since this could have happened on many many installs of CiviCRM, it would be ideal to have the update script fix the existing records (find newest and work backwards?).