xfrm: get rid of incorrect WARN

AFAICT this message is just printed whenever input validation fails.
This is a normal failure and we shouldn't be dumping the stack over it.

Looks like it was originally a printk that was maybe incorrectly
upgraded to a WARN:

commit 62db5cf
Author: stephen hemminger <shemminger@vyatta.com>
Date:   Wed May 12 06:37:06 2010 +0000

    xfrm: add severity to printk

Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/xfrm/xfrm_user.c

@@ -2117,7 +2117,7 @@ static int xfrm_add_acquire(struct sk_buff *skb, struct nlmsghdr *nlh,
 
 	err = verify_newpolicy_info(&ua->policy);
 	if (err)
-		goto bad_policy;
+		goto free_state;
 
 	/*   build an XP */
 	xp = xfrm_policy_construct(net, &ua->policy, attrs, &err);
@@ -2149,8 +2149,6 @@ static int xfrm_add_acquire(struct sk_buff *skb, struct nlmsghdr *nlh,
 
 	return 0;
 
-bad_policy:
-	WARN(1, "BAD policy passed\n");
 free_state:
 	kfree(x);
 nomem: