add kubernetes volumes to glance pod

Use kubernetes volumes for data storage rather than placing data
directly on the container filesystem.  That provides a starting point
for thinking about persistent data -- one could replace the emptyDir
source with an explicit path via hostDir, and then you would have
storage that would persist over a container delete/re-create.

Change-Id: Ifade1cb2ba546e5e0207c3d8c84965dc2195716b