If there is no GIT directory, archimport will assume it is an initial import.
It now also supports incremental imports, skipping "seen" commits. You can
now run it repeatedly to pull new commits from the Arch repository.
Signed-off-by: Martin Langhoff <martin@catalyst.net.nz>
Signed-off-by: Junio C Hamano <junkio@cox.net>