Fix for CVE-2014-3570 (with minor bn_asm.c revamp).

Reviewed-by: Emilia Kasper <emilia@openssl.org>
int rand_neg(void)
	{
	static unsigned int neg=0;
	static int sign[8]={0,0,0,1,1,0,1,1};

	return(sign[(neg++)%8]);
	}

int rand_neg(void)
	{
	static unsigned int neg=0;
	static int sign[8]={0,0,0,1,1,0,1,1};

	return(sign[(neg++)%8]);
	}
