describe: Make --tags and --all match lightweight tags more often

describe: Make --tags and --all match lightweight tags more often

If the caller supplies --tags they want the lightweight, unannotated
tags to be searched for a match.  If a lightweight tag is closer
in the history, it should be matched, even if an annotated tag is
reachable further back in the commit chain.

The same applies with --all when matching any other type of ref.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Acked-By: Uwe Kleine-König <ukleinek@strlen.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>