Apt gets confused if it talks to a mirror with an older index than the
index currently cached by apt. This can happen when image builds use a
newer index than the booted image. Avoid these problems entirely by
removing those index caches at the end of image building.
Change-Id: I245d516ee8a44831b2c29612b782bad555c48a3f
Co-Author: Clark Boylan <clark.boylan@gmail.com>
Signed-off-by: Paul Belanger <pabelanger@redhat.com>
