When an internal link is removed via the 'Remove' button in the link picker dialog, it's href attribute changes to "http://" instead.
Steps to reproduce:
1. login to the archetype CMS
2. edit a document
3. add an internal link
4. double-click the added internal link to re-open the link picker dialog
5. click the 'Remove' button
Expected: the added link is removed again
Actual: the link stays and is changed to <a href="http://">, resulting in an odd broken link in the front-end.
Workaround: remove the link via the 'remove link' button in the CKEditor toolbar instead.