Fix std::variant usage

This change makes it possible to use std::variant as a drop in
replacement for mapbox::variant.

Change-Id: Ia729c3a7832eec4dd6cddadba9bc160b6ba9ad90
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/functor.hpp b/functor.hpp
index ff60c7d..d00ec48 100644
--- a/functor.hpp
+++ b/functor.hpp
@@ -227,7 +227,8 @@
             return false;
         }
 
-        return _condition(std::forward<T>(it->second.template get<T>()));
+        return _condition(std::forward<T>(
+            sdbusplus::message::variant_ns::get<T>(it->second)));
     }
 
   private:
@@ -353,7 +354,8 @@
     {
         sdbusplus::message::variant<T> value;
         msg.read(value);
-        return _condition(std::forward<T>(value.template get<T>()));
+        return _condition(
+            std::forward<T>(sdbusplus::message::variant_ns::get<T>(value)));
     }
 
     /** @brief Retrieve a property value from inventory and test it.
diff --git a/test/test.cpp b/test/test.cpp
index 2327239..cf61b84 100644
--- a/test/test.cpp
+++ b/test/test.cpp
@@ -425,7 +425,8 @@
             sig.read(sigInterface);
             assert(sigInterface == "xyz.openbmc_project.Example.Iface1");
             sig.read(sigProperties);
-            assert(sigProperties["ExampleProperty1"] == "changed");
+            assert(sdbusplus::message::variant_ns::get<std::string>(
+                       sigProperties["ExampleProperty1"]) == "changed");
         }
     }
 }
diff --git a/utils.hpp b/utils.hpp
index aacee5e..2fd0805 100644
--- a/utils.hpp
+++ b/utils.hpp
@@ -26,8 +26,8 @@
     {
         static auto make(Arg&& arg)
         {
-            throw sdbusplus::message::variant_ns::bad_variant_access(
-                "in MakeVariantVisitor");
+            throw std::runtime_error(
+                "Invalid conversion in MakeVariantVisitor");
             return T();
         }
     };
@@ -67,8 +67,7 @@
 template <typename V, typename Arg>
 auto convertVariant(Arg&& v)
 {
-    return sdbusplus::message::variant_ns::apply_visitor(
-        MakeVariantVisitor<V>(), v);
+    return sdbusplus::message::variant_ns::visit(MakeVariantVisitor<V>(), v);
 }
 
 /** @struct CompareFirst