object: Report type in error when not user creatable.

Signed-off-by: NHani Benhabiles <hani@linux.com>
Reviewed-by: NHu Tao <hutao@cn.fujitsu.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

qmp.c

@@ -556,8 +556,8 @@ void object_add(const char *type, const char *id, const QDict *qdict,
     }
 
     if (!object_dynamic_cast(obj, TYPE_USER_CREATABLE)) {
-        error_setg(&local_err, "object '%s' isn't supported by object-add",
-                   id);
+        error_setg(&local_err, "object type '%s' isn't supported by object-add",
+                   type);
         goto out;
     }