Set keystone tokens to last 30 days.

The default for WMF wikis is 60 minutes, which was causing
sessions to break all over the place.

Bug 71731
Change-Id: Ieeb615291d666465e9e7da0a9d38839e0cfe429e
(cherry picked from commit 4ee211149018e718f9cbdfeb9887445a32bdf31a)