Make the index.html files the visible overview menu entry
(cherry picked from commit 1b9ab303

)
Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au>

The storage cache option layerinfo is deprecated,
so use blobdescriptor instead in example config files.
Signed-off-by: xg.song <xg.song@venusource.com>

Signed-off-by: Kelsey Hightower <kelsey.hightower@gmail.com>