sdbusplus: remove deprecated variant_ns

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I49cf41c9489246fbef7cd185fa01eb85350a2bce
diff --git a/sdbusplus.hpp b/sdbusplus.hpp
index 9e26b3b..f1722f4 100644
--- a/sdbusplus.hpp
+++ b/sdbusplus.hpp
@@ -74,7 +74,7 @@
             return false;
         }
 
-        return sdbusplus::message::variant_ns::get<Property>(value);
+        return std::get<Property>(value);
     }
 
     template <typename... Args>