'git update-index --verbose' consistently reports paths relative to the
work-tree root. The only exception is the '--again' option, which reports
paths relative to the current working directory.
Change do_reupdate to use non-prefixed paths.
Signed-off-by: Karsten Blees <blees@dcon.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>