When given a sub-command that it doesn't understand, 'git
multi-pack-index' dies with the following message:
$ git multi-pack-index bogus
fatal: unrecognized subcommand: bogus
Instead of 'die()'-ing, we can display the usage text, which is much
more helpful:
$ git.compile multi-pack-index bogus
error: unrecognized subcommand: bogus
usage: git multi-pack-index [<options>] write
or: git multi-pack-index [<options>] verify
or: git multi-pack-index [<options>] expire
or: git multi-pack-index [<options>] repack [--batch-size=<size>]
--object-dir <file> object directory containing set of packfile and pack-index pairs
--progress force progress reporting
While we're at it, clean up some duplication between the "no sub-command"
and "unrecognized sub-command" conditionals.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>