Asset metadata - commits don't show up

Description of problem:
When a user changes only the metadata of an asset, the commit for that change does not show up in the asset's history. Business user shouldn't need to be aware that there is another hidden file for the metadata of an asset. Moreover, if that commit isn't available from the asset itself, it is not possible to revert the change from the asset's history widgets.

Version-Release number of selected component (if applicable):
BRMS 6.1 DR4

Steps to Reproduce:
1. Open a drl, switch to Overview and and in it switch to Metadata.
2. Type something into Subject, save with a commit note "changing metadata".
3. Close and reopen the drl, switch to Overview (and Version history).

Actual results:
The "changing metadata" commit is not in the Version history table, it is not available from the versions widget on the editor's header menu.

Expected results:
The "changing metadata" commit is available.