image.bbclass: Make unneeded packages for a read-only rootfs configurable
Previously the list of packages that are considered unneeded for a
read-only rootfs was hardcoded. This made it impossible to, e.g., have
shadow installed on a system with a read-only rootfs, but where /etc
is mounted writable.
This also lists ${VIRTUAL-RUNTIME_update-alternatives} rather than
update-alternatives (as was previously the case) since this should
actually remove the intended package.
Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
