Trashed post section unexpectedly appears at root upon customize-save

Defect in 0.6.0:
1. Change a post's status to trash
2. Publish
3. Collapse the Posts panel to see the root of the Customizer.
4. See the trashed post section unexpectedly appear in the root.

<img width="305" alt="trashed-post-root-section" src="https://cloud.githubusercontent.com/assets/134745/15812640/411ae508-2b6c-11e6-9422-79a20dca410a.png">
