Consitently use dbus::utility types

This saves about 4k on the binary size

Tested: Redfish service validator passes.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I9546227a19c691b1aecb80e80307889548c0293f
diff --git a/include/hostname_monitor.hpp b/include/hostname_monitor.hpp
index 73c315f..f4e6b27 100644
--- a/include/hostname_monitor.hpp
+++ b/include/hostname_monitor.hpp
@@ -1,7 +1,7 @@
 #pragma once
 #ifdef BMCWEB_ENABLE_SSL
-#include <boost/container/flat_map.hpp>
 #include <dbus_singleton.hpp>
+#include <dbus_utility.hpp>
 #include <include/dbus_utility.hpp>
 #include <sdbusplus/bus/match.hpp>
 #include <sdbusplus/message/types.hpp>
@@ -43,20 +43,19 @@
 
     sdbusplus::message::message message(m);
     std::string iface;
-    boost::container::flat_map<std::string, dbus::utility::DbusVariantType>
-        changedProperties;
+    dbus::utility::DBusPropertiesMap changedProperties;
 
     message.read(iface, changedProperties);
-    auto it = changedProperties.find("HostName");
-    if (it == changedProperties.end())
+    const std::string* hostname = nullptr;
+    for (const auto& propertyPair : changedProperties)
     {
-        return 0;
+        if (propertyPair.first == "HostName")
+        {
+            hostname = std::get_if<std::string>(&propertyPair.second);
+        }
     }
-
-    std::string* hostname = std::get_if<std::string>(&it->second);
     if (hostname == nullptr)
     {
-        BMCWEB_LOG_ERROR << "Unable to read hostname";
         return 0;
     }