Update the rewrite rules in the nginx config

These rewrite rules were updated in httpd.conf but not the example
nginx.conf file.

The MP page redirect updates correspond to the change in:

   401796933c6adb2ec468c3df723579f6d8a455b9

... which was updated again in:

   f92768ebc3cf02b8a39f07ea51cd48d44619113f

The confirmation link update was from:

   bf4ee507b73999ece8d644e8da4d15617fb8fa18
Merge branch 'update-nginx-config'