rtnl: Bail out if interface name is blacklisted

read_uevent() checks if the interface name is blacklisted, but then
continues to open the corresponding uevent file, and happily sets SERIVCE_TYPE
and DEVICE_TYPE (nullifying the blacklisting)

this leads to the following logging when starting connmand -I wlan0
  Ignoring interface wlan0 (filtered)
  Adding interface wlan0 [ wifi ]

fix this by bailing out from read_uevent() as soon as we find the device
is blacklisted

connman/src/rtnl.c

@@ -132,6 +132,7 @@ static void read_uevent(struct interface_data *interface)
 	if (ether_blacklisted(name)) {
 		interface->service_type = CONNMAN_SERVICE_TYPE_UNKNOWN;
 		interface->device_type = CONNMAN_DEVICE_TYPE_UNKNOWN;
+		goto out;
 	} else {
 		interface->service_type = CONNMAN_SERVICE_TYPE_ETHERNET;
 		interface->device_type = CONNMAN_DEVICE_TYPE_ETHERNET;