Trivially refactor an assignment to make a subsequent patch
smaller. The "ref_nr" variable is initialized to 0 earlier, just as
"j" is, and "j" is only incremented in that loop, so this change isn't
a logic error.
This change simplifies a subsequent change, which will split the
incrementing of "ref_nr" into two blocks.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>