index-pack.c: correctly initialize appended objects

When index-pack completes a thin pack it appends objects to the pack.
Since the commit 92392b4(index-pack: Honor core.deltaBaseCacheLimit when
resolving deltas) such an object can be pruned in case of memory
pressure, and will be read back again by get_data_from_pack().  For this
to work, the fields in object_entry structure need to be initialized
properly.

Noticed by Pierre Habouzit.

Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Acked-by: Nicolas Pitre <nico@cam.org>
Acked-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

index-pack.c

@@ -698,6 +698,10 @@ static struct object_entry *append_obj_to_pack(
 	write_or_die(output_fd, header, n);
 	obj[0].idx.crc32 = crc32(0, Z_NULL, 0);
 	obj[0].idx.crc32 = crc32(obj[0].idx.crc32, header, n);
+	obj[0].size = size;
+	obj[0].hdr_size = n;
+	obj[0].type = type;
+	obj[0].real_type = type;
 	obj[1].idx.offset = obj[0].idx.offset + n;
 	obj[1].idx.offset += write_compressed(output_fd, buf, size, &obj[0].idx.crc32);
 	hashcpy(obj->idx.sha1, sha1);