Switch to pd-ssd for default GCE disk type
Switch to pd-ssd for default GCE disk type

Acidburn0zzz/worker,travis-ci/worker,Acidburn0zzz/worker,henrikhodne-abandoned/worker,solarce/worker,solarce/worker,henrikhodne-abandoned/worker,solarce/worker,travis-ci/worker,Acidburn0zzz/worker,henrikhodne-abandoned/worker,travis-ci/worker