pack-objects: limit scope in 'add_object_entry_from_pack()'

In add_object_entry_from_pack() we declare 'revs' (given to us through
the miscellaneous context argument) earlier in the "if (p)" conditional
than is necessary.  Move it down as far as it can go to reduce its
scope.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: ttaylorr

builtin/pack-objects.c

@@ -3725,14 +3725,14 @@ static int add_object_entry_from_pack(const struct object_id *oid,
 		return 0;
 
 	if (p) {
-		struct rev_info *revs = _data;
 		struct object_info oi = OBJECT_INFO_INIT;
 
 		oi.typep = &type;
 		if (packed_object_info(the_repository, p, ofs, &oi) < 0) {
 			die(_("could not get type of object %s in pack %s"),
 			    oid_to_hex(oid), p->pack_name);
 		} else if (type == OBJ_COMMIT) {
+			struct rev_info *revs = _data;
 			/*
 			 * commits in included packs are used as starting points for the
 			 * subsequent revision walk