Make Horizon's SECURITY_KEY 64 characters long
Make Horizon's SECURITY_KEY 64 characters long

Our own security guide recommends it:
https://docs.openstack.org/security-guide/dashboard/secret-key.html

Change-Id: I7c85e9ff8b3bc92b80a3d0728f299ed1e4cb436c

dprince/tripleo-heat-templates,openstack/tripleo-heat-templates,openstack/tripleo-heat-templates,dprince/tripleo-heat-templates