[PATCH] archimport: avoid committing on an Arch tag

[PATCH] archimport: avoid committing on an Arch tag

Arch tags are full commits (without any changed files) as well. Trust Arch
to have put an unchanged tree in place (which seems to do reliably), and
just add a tag & new branch. Speeds up Arch imports significantly, and leaves
history in a much saner state.

Signed-off-by: Martin Langhoff <martin@catalyst.net.nz>
Signed-off-by: Junio C Hamano <junkio@cox.net>