bonding: fix two compiler warnings

Fix two compiler warnings that are new with recent versions of gcc
(apparently 4.2 and up). One is fixed by refactoring; this change was
supplied by Stephen Hemminger. The other was fixed by labelling the
variable as uninitialized_var() after confirming via inspection that it
cannot actually be used uninitialized.

Signed-off-by: Jay Vosburgh <[e-mail]>
Signed-off-by: Stephen Hemminger <[e-mail]>
Signed-off-by: Jeff Garzik <[e-mail]>

drivers/net/bonding/bond_alb.c

···
 		}
 
 		if (!list_empty(&bond->vlan_list)) {
-			unsigned short vlan_id;
-			int res = vlan_get_tag(skb, &vlan_id);
-			if (!res) {
+			if (!vlan_get_tag(skb, &client_info->vlan_id))
 				client_info->tag = 1;
-				client_info->vlan_id = vlan_id;
-			}
 		}
 
 		if (!client_info->assigned) {

drivers/net/bonding/bond_main.c

···
  */
 int bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb, struct net_device *slave_dev)
 {
-	unsigned short vlan_id;
+	unsigned short uninitialized_var(vlan_id);
 
 	if (!list_empty(&bond->vlan_list) &&
 	    !(slave_dev->features & NETIF_F_HW_VLAN_TX) &&