Show peeled onion from upload-pack and server-info.

Show peeled onion from upload-pack and server-info.

This updates git-ls-remote to show SHA1 names of objects that are
referred by tags, in the "ref^{}" notation.

This would make git-findtags (without -t flag) almost trivial.

    git-peek-remote . |
    sed -ne "s:^$target	"'refs/tags/\(.*\)^{}$:\1:p'

Also Pasky could do:

    git-ls-remote --tags $remote |
    sed -ne 's:\(	refs/tags/.*\)^{}$:\1:p'

to find out what object each of the remote tags refers to, and
if he has one locally, run "git-fetch $remote tag $tagname" to
automatically catch up with the upstream tags.

Signed-off-by: Junio C Hamano <junkio@cox.net>