sparse-checkout: improve OS ls compatibility

sparse-checkout: improve OS ls compatibility

On FreeBSD, when executed by root ls enables the '-A' option:

  -A  Include directory entries whose names begin with a dot (`.')
      except for . and ...  Automatically set for the super-user unless
      -I is specified.

As a result the .git directory appeared in the output when run as root.
Simulate no-dotfile ls behaviour using a shell glob.

Helped-by: Eric Wong <e@80x24.org>
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Ed Maste <emaste@FreeBSD.org>
Acked-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>