net: convert BUG_TRAP to generic WARN_ON

Removes legacy reinvent-the-wheel type thing. The generic
machinery integrates much better to automated debugging aids
such as kerneloops.org (and others), and is unambiguous due to
better naming. Non-intuively BUG_TRAP() is actually equal to
WARN_ON() rather than BUG_ON() though some might actually be
promoted to BUG_ON() but I left that to future.

I could make at least one BUILD_BUG_ON conversion.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
index 800f669..c609a4b 100644
--- a/net/xfrm/xfrm_ipcomp.c
+++ b/net/xfrm/xfrm_ipcomp.c
@@ -22,7 +22,6 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/percpu.h>
-#include <linux/rtnetlink.h>
 #include <linux/smp.h>
 #include <linux/vmalloc.h>
 #include <net/ip.h>
@@ -251,7 +250,7 @@
 			break;
 	}
 
-	BUG_TRAP(pos);
+	WARN_ON(!pos);
 
 	if (--pos->users)
 		return;