initializer: Call a tiny instance "preemptible" instead of spot
initializer: Call a tiny instance "preemptible" instead of spot

This makes it consistent with an earlier prompt in the workflow.

NetSys/quilt,kklin/quilt,LuiseV/quilt,NetSys/quilt,kklin/kelda,NetSys/quilt,kklin/quilt,kklin/quilt,ejj/quilt-dev,NetSys/quilt,kklin/kelda,quilt/quilt,quilt/quilt,LuiseV/quilt,LuiseV/quilt,LuiseV/quilt,ejj/quilt-dev,quilt/quilt,ejj/quilt-dev,LuiseV/quilt,kelda/kelda,NetSys/quilt,kelda/kelda,kklin/kelda,kelda/kelda,quilt/quilt,kklin/quilt,kklin/kelda,kelda/kelda,ejj/quilt-dev