Move to sha-specified test image for nanoserver
Move to sha-specified test image for nanoserver

Signed-off-by: Phil Estes <dbac1f450dc8326caa7ba104b384a0eca642250c@linux.vnet.ibm.com>

thaJeztah/containerd,crosbymichael/containerd,thaJeztah/containerd,dmcgowan/containerd,estesp/containerd,mikebrow/containerd,containerd/containerd,crosbymichael/containerd,containerd/containerd,vdemeester/containerd,estesp/containerd,mikebrow/containerd,vdemeester/containerd,dmcgowan/containerd