Refactor MessageFactory

While we're here, also drop struct keywords where we use Linux structures.

Bug: 162032964
Test: canhalctrl up test virtual vcan3
Change-Id: Ib629cad3d2203b998668f45534699292863cadd9
diff --git a/automotive/can/1.0/default/libnetdevice/vlan.cpp b/automotive/can/1.0/default/libnetdevice/vlan.cpp
index 33dc029..ee02f7b 100644
--- a/automotive/can/1.0/default/libnetdevice/vlan.cpp
+++ b/automotive/can/1.0/default/libnetdevice/vlan.cpp
@@ -33,18 +33,18 @@
         return false;
     }
 
-    nl::MessageFactory<struct ifinfomsg> req(RTM_NEWLINK,
-                                             NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL | NLM_F_ACK);
-    req.addattr(IFLA_IFNAME, vlan);
-    req.addattr<uint32_t>(IFLA_LINK, ethidx);
+    nl::MessageFactory<ifinfomsg> req(RTM_NEWLINK,
+                                      NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL | NLM_F_ACK);
+    req.add(IFLA_IFNAME, vlan);
+    req.add<uint32_t>(IFLA_LINK, ethidx);
 
     {
-        auto linkinfo = req.nest(IFLA_LINKINFO);
-        req.addattr(IFLA_INFO_KIND, "vlan");
+        auto linkinfo = req.addNested(IFLA_LINKINFO);
+        req.add(IFLA_INFO_KIND, "vlan");
 
         {
-            auto linkinfo = req.nest(IFLA_INFO_DATA);
-            req.addattr(IFLA_VLAN_ID, id);
+            auto linkinfo = req.addNested(IFLA_INFO_DATA);
+            req.add(IFLA_VLAN_ID, id);
         }
     }