Correct the buggy return instruction.
diff --git a/src/device.c b/src/device.c
index bef235d..a360e3b 100644
--- a/src/device.c
+++ b/src/device.c
@@ -791,7 +791,7 @@
 
 	reply = dbus_message_new_method_return(msg);
 	if (!reply)
-		return;
+		return NULL;
 	sdp_data_t *curr;
 	sdp_list_t *ap = 0;
 	for (; attr; attr = attr->next) {