Fixup mapbox variant references

This removes all dependencies on the mapbox specific variant api. The
code is now compatible with the drop in std::variant api.

Change-Id: Ie64be86ecae341def54f564eb282fb3b5356cc18
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/include/dbus_singleton.hpp b/include/dbus_singleton.hpp
index 2438152..9fe966f 100644
--- a/include/dbus_singleton.hpp
+++ b/include/dbus_singleton.hpp
@@ -1,20 +1,16 @@
 #pragma once
 #include <iostream>
 #include <sdbusplus/asio/connection.hpp>
+#include <sdbusplus/message/types.hpp>
+#include <type_traits>
 
 namespace mapbox
 {
 template <typename T, typename... Types>
-const T* getPtr(const mapbox::util::variant<Types...>& v)
+const T* getPtr(const sdbusplus::message::variant<Types...>& v)
 {
-    if (v.template is<std::remove_const_t<T>>())
-    {
-        return &v.template get_unchecked<std::remove_const_t<T>>();
-    }
-    else
-    {
-        return nullptr;
-    }
+    namespace variant_ns = sdbusplus::message::variant_ns;
+    return variant_ns::get_if<std::remove_const_t<T>, Types...>(&v);
 }
 } // namespace mapbox