bug 1370594: Make redesign notices exclusive
bug 1370594: Make redesign notices exclusive

Ensure redesign_beta and redesign_live notices aren't displayed at
the same time.

SphinxKnight/kuma,jwhitlock/kuma,a2sheppy/kuma,jwhitlock/kuma,a2sheppy/kuma,jwhitlock/kuma,mozilla/kuma,jwhitlock/kuma,Elchi3/kuma,a2sheppy/kuma,mozilla/kuma,a2sheppy/kuma,Elchi3/kuma,Elchi3/kuma,SphinxKnight/kuma,Elchi3/kuma,jwhitlock/kuma,SphinxKnight/kuma,mozilla/kuma,SphinxKnight/kuma,mozilla/kuma,escattone/kuma,SphinxKnight/kuma,a2sheppy/kuma,escattone/kuma,Elchi3/kuma,SphinxKnight/kuma,escattone/kuma,mozilla/kuma