ifenslave: Fix unused variable warnings.

Documentation/networking/ifenslave.c: In function ‘if_getconfig’:
Documentation/networking/ifenslave.c:508:14: warning: variable ‘mtu’ set but not used [-Wunused-but-set-variable]
Documentation/networking/ifenslave.c:508:6: warning: variable ‘metric’ set but not used [-Wunused-but-set-variable]

The purpose of this function is to simply print out the values
it probes, so...
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/ifenslave.c

@@ -539,12 +539,14 @@ static int if_getconfig(char *ifname)
 		metric = 0;
 	} else
 		metric = ifr.ifr_metric;
+	printf("The result of SIOCGIFMETRIC is %d\n", metric);
 
 	strcpy(ifr.ifr_name, ifname);
 	if (ioctl(skfd, SIOCGIFMTU, &ifr) < 0)
 		mtu = 0;
 	else
 		mtu = ifr.ifr_mtu;
+	printf("The result of SIOCGIFMTU is %d\n", mtu);
 
 	strcpy(ifr.ifr_name, ifname);
 	if (ioctl(skfd, SIOCGIFDSTADDR, &ifr) < 0) {