entry: switch AdditionalData to dict

Clients have been switched to use AddtionalData2, which is a
dictionary.  Move AdditionalData also to a dictionary so we
can stage a removal of AdditionalData2.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I7cc9591895f219471ac098387f72a35c18e6c750
diff --git a/elog_serialize.cpp b/elog_serialize.cpp
index 6a2dac4..a0f42be 100644
--- a/elog_serialize.cpp
+++ b/elog_serialize.cpp
@@ -108,7 +108,7 @@
     e.severity(severity, true);
     e.timestamp(timestamp, true);
     e.message(message, true);
-    e.additionalData(util::additional_data::combine(additionalData), true);
+    e.additionalData(additionalData, true);
     e.additionalData2(additionalData, true);
     e.sdbusplus::server::xyz::openbmc_project::logging::Entry::resolved(
         resolved, true);