Adapt the name of the `block_writer::buf` variable to instead be called
`block`. This aligns it with the existing `block_len` variable, which
tracks the length of this buffer, and is generally a bit more tied to
the actual context where this variable gets used.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
aa248b8ab2