redhat/configs/evaluate_configs: Add find dead configs option

The kernel's CONFIG entries are under a constant state of change. New
CONFIG entries are added and removed every upstream release. In
kernel-ark we track CONFIG values with unique CONFIG files in the
redhat/configs/* directories. It is often the case that we forget to
remove a CONFIG file when the CONFIG is removed from the upstream kernel.
This results in stale or "dead" config files in redhat/configs.

Add an option "-D" to evaluate_configs to identify and remove these
files, commit the resulting changes, and add two fixup CONFIG changes.

Signed-off-by: Prarit Bhargava prarit@redhat.com