treewide: Cleanup unused includes

Change-Id: Ied2a0d97d2c31dc2b370452768a7f41d9ecf07f3
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/dhcp_configuration.cpp b/src/dhcp_configuration.cpp
index 53d4e91..6c96206 100644
--- a/src/dhcp_configuration.cpp
+++ b/src/dhcp_configuration.cpp
@@ -2,6 +2,7 @@
 
 #include "config_parser.hpp"
 #include "network_manager.hpp"
+#include "util.hpp"
 
 #include <phosphor-logging/elog-errors.hpp>
 #include <phosphor-logging/log.hpp>