On Windows, we do not have functions srandom() and random(). Use srand()
and rand(). These functions produce random numbers of lesser quality,
but for the purpose (a retry time-out) they are still good enough.
Signed-off-by: Johannes Sixt <j6t@kdbg.org> Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>