Revision deletion is not removing the tag from the database.

Issue Summary

I created three revisions of a node and assigned three revision tags to them. Then I deleted one of the revisions. The revision tag listing page now rightly displays the remaining two revisions (since it relies on node_revision_list() ). But in the "revision_tags" table in the database, the deleted revision and the corresponding tag remains. I am using non-unique tags. Thanks.