openvswitch: Fix memory leak.

Need to free memory in case of sample action error.

Introduced by commit 651887b0 ("openvswitch: Sample
action without side effects").
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>

net/openvswitch/actions.c

@@ -722,8 +722,6 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 
 		case OVS_ACTION_ATTR_SAMPLE:
 			err = sample(dp, skb, key, a);
-			if (unlikely(err)) /* skb already freed. */
-				return err;
 			break;
 		}