Each submodule subcommand has specific long-options. Therefore, teach
bash completion to support option completion based on the current
subcommand. All long-options that are mentioned in the man-page synopsis
are added.
Signed-off-by: Cornelius Weig <cornelius.weig@tngtech.com> Reviewed-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>