sdbusplus: replace message::variant with std::variant

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: If7c54cfe20a84fa91aacc309ebfa804231078bf7
diff --git a/chassis_state_manager.cpp b/chassis_state_manager.cpp
index c8a0665..17db4df 100644
--- a/chassis_state_manager.cpp
+++ b/chassis_state_manager.cpp
@@ -71,7 +71,7 @@
 //        has read property function
 void Chassis::determineInitialState()
 {
-    sdbusplus::message::variant<int> pgood = -1;
+    std::variant<int> pgood = -1;
     auto method = this->bus.new_method_call(
         "org.openbmc.control.Power", "/org/openbmc/control/power0",
         "org.freedesktop.DBus.Properties", "Get");
@@ -152,7 +152,7 @@
 
 bool Chassis::stateActive(const std::string& target)
 {
-    sdbusplus::message::variant<std::string> currentState;
+    std::variant<std::string> currentState;
     sdbusplus::message::object_path unitTargetPath;
 
     auto method = this->bus.new_method_call(SYSTEMD_SERVICE, SYSTEMD_OBJ_PATH,