Block user confirmation cancel link destination broken

When I click "Block author" on a message, and then "Cancel", I'm sent to the messages overview screen, and not back to the thread.

This is obviously a bug, as the code already attempts to keep the thread location as query string '?destination=', but fails to add that query string to the link. That's because pm_block_user.module adds array('query' => path ) to the variables, so that l() gets '0' => array('query' => path ), where it expects just 'query' => path, and so it doesn't see the query element.

Attached patch fixes it for me, cancel link now works as expected (i.e. goes back to where I clicked the operation being cancelled).