sdbusplus: remove deprecated variant_ns

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ie9d2f9838212aba7e3201f8af43586c48e273189
diff --git a/bmc_state_manager.cpp b/bmc_state_manager.cpp
index 1ab3f7e..1b7d311 100644
--- a/bmc_state_manager.cpp
+++ b/bmc_state_manager.cpp
@@ -75,8 +75,7 @@
         return;
     }
 
-    auto currentStateStr =
-        sdbusplus::message::variant_ns::get<std::string>(currentState);
+    auto currentStateStr = std::get<std::string>(currentState);
     if (currentStateStr == activeState)
     {
         log<level::INFO>("Setting the BMCState field",