MAGETWO-71375: Zero Subtotal Orders have incorrect status

- Update automated test according to review

Author: lusinehak

app/code/Magento/Checkout/Test/Mftf/Test/ZeroSubtotalOrdersWithProcessingStatusTest.xml

@@ -36,7 +36,7 @@
             <createData entity="DefaultShippingMethodsConfig" stepKey="defaultShippingMethodsConfig"/>
             <createData entity="DisableFreeShippingConfig" stepKey="disableFreeShippingConfig"/>
             <createData entity="DisablePaymentMethodsSettingConfig" stepKey="disablePaymentMethodsSettingConfig"/>
-            <amOnPage url="admin/admin/auth/logout/" stepKey="amOnLogoutPage"/>
+            <actionGroup ref="logout" stepKey="logout"/>
             <deleteData createDataKey="simpleproduct" stepKey="deleteProduct"/>
             <deleteData createDataKey="simplecategory" stepKey="deleteCategory"/>
         </after>