Fix remaining instances where "pack-file" is used instead of
"packfile". Some places remain where we still use "pack-file",
This is the case when we explicitly refer to a file with a
".pack" extension as opposed to a data source providing a pack
data stream.
Signed-off-by: NPatrick Steinhardt <ps@pks.im>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>