Remove adding an empty interface

```
terminate called after throwing an instance of 'sdbusplus::exception::SdBusError'
what():  sd_bus_add_object_vtable: org.freedesktop.DBus.Error.InvalidArgs:
Invalid argument
```
phosphor-srvcfg-manager is throwing the above exception and coredumping.
Adding an empty interface will throw an exception after the below change in
sdbusplus.

https://github.com/openbmc/sdbusplus/commit/017a19da5f67a74daedf4d63111569902d4764e6
https://github.com/openbmc/sdbusplus/commit/fb0366b5c15d196c62498b8c3c35c5231c372262

Tested:

1) Patched witherspoon-tacoma and phosphor-srvcfg-manager did not coredump.
2) ObjectManager interface is implemented by /xyz/openbmc_project/control/service.
3) Disabled and enabled net-ipmi successfully.

Signed-off-by: Tom Joseph <tomjoseph@in.ibm.com>
Change-Id: I5e66f0244c07345b5caea5f94578bf0592b4a91a
diff --git a/src/main.cpp b/src/main.cpp
index e57c767..4eea773 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -306,9 +306,6 @@
     initTimer = std::make_unique<boost::asio::steady_timer>(io);

     conn->request_name(phosphor::service::serviceConfigSrvName);

     auto server = sdbusplus::asio::object_server(conn, true);

-    auto mgrInterface =

-        server.add_interface(phosphor::service::srcCfgMgrBasePath, "");

-    mgrInterface->initialize();

     server.add_manager(phosphor::service::srcCfgMgrBasePath);

     // Initialize the objects after systemd indicated startup finished.

     auto userUpdatedSignal = std::make_unique<sdbusplus::bus::match::match>(