Clean up left-over references to configure_backend action

The unused configure_backend action was removed with commit
49790088.

src/kleopatra.rc

@@ -66,8 +66,6 @@
             <Separator/>
             <Action name="crl_clear_crl_cache"/>
             <Action name="crl_dump_crl_cache"/>
-            <Separator/>
-            <Action name="configure_backend"/>
         </Menu>
         <Menu name="settings">
             <text>&amp;Settings</text>

src/mainwindow.cpp

@@ -475,10 +475,6 @@ void MainWindow::Private::setupActions()
         }
     }
 
-    if (QAction *action = coll->action(QStringLiteral("configure_backend"))) {
-        action->setMenuRole(QAction::NoRole);    //prevent Qt OS X heuristics for config* actions
-    }
-
     KStandardAction::close(q, SLOT(close()), coll);
     KStandardAction::quit(q, SLOT(closeAndQuit()), coll);
     KStandardAction::configureToolbars(q, SLOT(configureToolbars()), coll);