Removed unused includes

The clangd LSP indicates when includes aren't used directly.

Tested:
Unit tests pass

Change-Id: I0306be1439317ff40981a8bf221ea7d8a652e281
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/elog_serialize.cpp b/elog_serialize.cpp
index 5c0f9cb..71bd986 100644
--- a/elog_serialize.cpp
+++ b/elog_serialize.cpp
@@ -2,6 +2,8 @@
 
 #include "elog_serialize.hpp"
 
+#include "util.hpp"
+
 #include <cereal/archives/binary.hpp>
 #include <cereal/types/map.hpp>
 #include <cereal/types/string.hpp>