fsck: don't put a void*-shaped peg in a char*-shaped hole

fsck: don't put a void*-shaped peg in a char*-shaped hole

The source of this nonsense was

    04d3975937 fsck: reduce stack footprint

, which wedged a pointer to parent into the object_array_entry's name
field.  The parent pointer was passed to traverse_one_object(), even
though that function *didn't use it*.

The useless code has been deleted over time.  Commit

    a1cdc25172 fsck: drop unused parameter from traverse_one_object()

removed the parent pointer from traverse_one_object()'s
signature. Commit

    c0aa335c95 Remove unused variables

removed the code that read the parent pointer back out of the name
field.

This commit takes the last step: don't write the parent pointer into
the name field in the first place.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>