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

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ifc7c680ca196882d890d8b7061fe56428285c276
diff --git a/src/processing.cpp b/src/processing.cpp
index b0c73b3..229f417 100644
--- a/src/processing.cpp
+++ b/src/processing.cpp
@@ -111,8 +111,8 @@
 
         if (interfacePair.first == assocDefsInterface)
         {
-            const sdbusplus::message::variant<std::vector<Association>>*
-                variantAssociations = nullptr;
+            const std::variant<std::vector<Association>>* variantAssociations =
+                nullptr;
             for (const auto& interface : interfacePair.second)
             {
                 if (interface.first == assocDefsProperty)