numa: Flatten simple union NumaOptions

Simple unions are simpler than flat unions in the schema, but more
complicated in C and on the QMP wire: there's extra indirection in C
and extra nesting on the wire, both pointless.  They're best avoided
in new code.

NumaOptions isn't new, but it's only used internally, not in QMP.
Convert it to a flat union.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1487709988-14322-2-git-send-email-armbru@redhat.com>

numa.c

@@ -228,8 +228,8 @@ static int parse_numa(void *opaque, QemuOpts *opts, Error **errp)
     }
 
     switch (object->type) {
-    case NUMA_OPTIONS_KIND_NODE:
-        numa_node_parse(object->u.node.data, opts, &err);
+    case NUMA_OPTIONS_TYPE_NODE:
+        numa_node_parse(&object->u.node, opts, &err);
         if (err) {
             goto end;
         }

qapi-schema.json

@@ -5570,6 +5570,14 @@
             '*head'  : 'int',
             'events' : [ 'InputEvent' ] } }
 
+##
+# @NumaOptionsType:
+#
+# Since: 2.1
+##
+{ 'enum': 'NumaOptionsType',
+  'data': [ 'node' ] }
+
 ##
 # @NumaOptions:
 #
@@ -5578,6 +5586,8 @@
 # Since: 2.1
 ##
 { 'union': 'NumaOptions',
+  'base': { 'type': 'NumaOptionsType' },
+  'discriminator': 'type',
   'data': {
     'node': 'NumaNodeOptions' }}