Remove dbus_singleton.hpp

dbus_singleton is now removed as we dont want global access of
systemBus anymore.

This allows platforms without plugins to compile

Change-Id: I9b4208407273d3a3fb79573955b42142fa05c792
Signed-off-by: Edward Lee <edwarddl@google.com>

example_platform_plugin.cpp

diff --git a/example_platform_plugin.cpp b/example_platform_plugin.cpp
index a8209c3..e784e84 100644
--- a/example_platform_plugin.cpp
+++ b/example_platform_plugin.cpp
@@ -1,7 +1,6 @@
 #include <cstdint>
 
 #include <bmcweb_plugins/async_resp.hpp>
-#include <bmcweb_plugins/dbus_singleton.hpp>
 #include <bmcweb_plugins/dbus_utils.hpp>
 #include <bmcweb_plugins/http_request.hpp>
 #include <bmcweb_plugins/interface.hpp>
@@ -23,7 +22,7 @@
 void redfishGetReplacedManagedStore(
     const crow::Request& req,
     const std::shared_ptr<bmcweb::AsyncResp>& asyncResp) {
-  if (!redfish::setUpRedfishRoute(req, asyncResp)) {
+  if (!redfish::setUpRedfishRouteOnGlobalApp(req, asyncResp)) {
     return;
   }
   managedStore::ManagedObjectStoreContext requestContext(asyncResp);
@@ -56,10 +55,10 @@
 
 void redfishGetReplaced(const crow::Request& req,
                         const std::shared_ptr<bmcweb::AsyncResp>& asyncResp) {
-  if (!redfish::setUpRedfishRoute(req, asyncResp)) {
+  if (!redfish::setUpRedfishRouteOnGlobalApp(req, asyncResp)) {
     return;
   }
-  crow::connections::systemBus->async_method_call(
+  managedStore::GetManagedObjectStore()->postDbusCallToIoContext(
       [asyncResp](const boost::system::error_code ec,
                   const std::variant<std::string>&) {
         if (ec) {