Activity links from park pages don't work

[ebrelsford]

For example, go to this park, click any of the activity buttons. The URL changes but as the component tries to unmount it gets to this line and fails because the event listener is not passed to removeEventListener.

[gregallensworth]

Rephrase copied from 649:

http://www.caliparks.org/park/14224

Click an activity icon, which should link to the same target as the Explore activities. The URL changes in the address bar, but it doesn't actually change over.

Dan pasted this link, which may be relevant:
https://github.com/GreenInfo-Network/caliparks.org/blob/250a781e5ed98a3e1f39e71394f3d1c79a6fcb06/app/public/routes.jsx

Sean has this, which may be relevant: