no need to support sac any longer.

Reference: /n/patches.lsub.org/patch/nosac
Date: Wed Jul  4 04:17:24 CES 2012
Signed-off-by: quanstro@quanstro.net

# rm /sys/src/nix/boot/sac.c

--- /sys/src/nix/boot/boot.h	Fri Jun 29 11:32:52 2012
+++ /sys/src/nix/boot/boot.h	Wed Jul  4 03:22:09 2012
@@ -61,9 +61,6 @@
 extern void	configlocal(Method*);
 extern int	connectlocal(void);
 
-extern void	configsac(Method*);
-extern int	connectsac(void);
-
 extern void	configpaq(Method*);
 extern int	connectpaq(void);