When we have a config file with multiple sections, we might want to
exclude certain config sections from running. Rather than specifying
all the section we want to run, add a "-S <section>" option to build
up a list of sections to exclude.

This is useful if a given section config is known to cause a fatal
failure,but you still want to run all the other config sections.

Also add support to the setup program that emits the currently
configured setup for each section in the config file.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>