Merge branch 'jk/pack-shallow-always-without-bitmap'

Reachability bitmaps do not work with shallow operations.
Fixes regression in 2.0.

* jk/pack-shallow-always-without-bitmap:
  pack-objects: turn off bitmaps when we see --shallow lines

builtin/pack-objects.c

@@ -2494,6 +2494,7 @@ static void get_object_list(int ac, const char **av)
 				if (get_sha1_hex(line + 10, sha1))
 					die("not an SHA-1 '%s'", line + 10);
 				register_shallow(sha1);
+				use_bitmap_index = 0;
 				continue;
 			}
 			die("not a rev '%s'", line);