treewide: Cleanup unused includes

Change-Id: Ied2a0d97d2c31dc2b370452768a7f41d9ecf07f3
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/test/mock_network_manager.hpp b/test/mock_network_manager.hpp
index fde3bbd..337af88 100644
--- a/test/mock_network_manager.hpp
+++ b/test/mock_network_manager.hpp
@@ -1,6 +1,7 @@
 #pragma once
 #include "mock_ethernet_interface.hpp"
 #include "network_manager.hpp"
+#include "util.hpp"
 
 #include <gmock/gmock.h>