Windows base layers are no longer the special "layers+base" type, so we can remove all the special handling for that.
Signed-off-by: Stefan J. Wernli <swernli@microsoft.com>
Previously, Windows only supported running with a OS-managed base image.
With this change, Windows supports normal, Linux-like layered images, too.
Signed-off-by: John Starks <jostarks@microsoft.com>