dbus: remove duplicate property for credential item

kordophoned/include/net.buzzert.kordophonecd.Server.xml

@@ -73,10 +73,6 @@
             <arg name="user" type="s" direction="in"/>
         </method>
 
-        <method name="SetCredentialItem">
-            <arg name="item_path" type="o" direction="in"/>
-        </method>
-
         <!-- emitted when anything changes -->
         <signal name="ConfigChanged"/>        
     </interface>

kordophoned/src/dbus/server_impl.rs

@@ -112,16 +112,6 @@ impl DbusSettings for ServerImpl {
         )
     }
 
-    fn set_credential_item_(&mut self, item_path: dbus::Path<'static>) -> Result<(), dbus::MethodErr> {
-        self.send_event_sync(|r| 
-            Event::UpdateSettings(Settings {
-                server_url: None,
-                username: None,
-                credential_item: Some(item_path.to_string()),
-            }, r)
-        )
-    }
-
     fn server_url(&self) -> Result<String, dbus::MethodErr> {
         self.send_event_sync(Event::GetAllSettings)
             .map(|settings| settings.server_url.unwrap_or_default())