Remove fungi's temporary summit and old 2012 keys

* modules/openstack_project/manifests/users.pp: Remove the temporary
SSH key used for any emergency systems administration during the
Icehouse summit, and also remove the old SSH key from 2012 which has
been replaced pursuant to the infra SSH policy.

Change-Id: I3099038006eb512c85bfcb2c0afa2cfe862f4c0d