As the man page says, "unsupported, experimental, and barely
functional".  The last even minor updates to any of this were back in
2004, presumably it's not getting better any time soon.

This is also the only GC ops implementation in the tree that actually
falls all the way down to the spans routines for everything, so that's
pretty nice to be rid of.

v2: Fix stray break statement (Jon)

Reviewed-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Signed-off-by: Adam Jackson <ajax@redhat.com>