These flags are already known to rev-parse and have the same meaning.

This patch allows to run gitk as follows:

	gitk --branches --not --remotes

to show only your local work.
Signed-off-by: NUwe Kleine-König <Uwe.Kleine-Koenig@digi.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>