double declaration of Conf removed.

Reference: /n/sources/patch/applied/ipconfignit
Date: Mon Apr 30 17:50:52 CES 2012
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/ip/ipconfig/ipconfig.h	Mon Apr 30 17:50:29 2012
+++ /sys/src/cmd/ip/ipconfig/ipconfig.h	Mon Apr 30 17:50:28 2012
@@ -81,8 +81,6 @@
 
 extern Ctl *firstctl, **ctll;
 
-extern Conf conf;
-
 extern int	noconfig;
 extern int	ipv6auto;
 extern int	debug;