Quicksand - fix spooky back button issue

Summary: Fixes T7911.

Test Plan:

• load a page
• click something else
• go back to original page via clicking
• browser refresh
• click something else
• browser back -- and it now works!

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T7911

Differential Revision: https://secure.phabricator.com/D12603