Remove git-status from list of scripts as it is builtin

Now that git-status is builtin on Cygwin this compiles as
git-status.exe.  We cannot continue to include git-status
as a Makefile target as it will never be built.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>