[NET]: Don't declare extern variables in net/core/sysctl_net_core.c

Some are already declared in include/linux/netdevice.h, while
some others (xfrm ones) need to be declared.

The driver/net/rrunner.c just uses same extern as well, so
cleanup it also.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 688f6f5..58dfa828 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -37,6 +37,8 @@
 extern struct sock *xfrm_nl;
 extern u32 sysctl_xfrm_aevent_etime;
 extern u32 sysctl_xfrm_aevent_rseqth;
+extern int sysctl_xfrm_larval_drop;
+extern u32 sysctl_xfrm_acq_expires;
 
 extern struct mutex xfrm_cfg_mutex;