Replacing deprecated methods in Magento_Backup module.

Author: tiagosampaio

app/code/Magento/Backup/Controller/Adminhtml/Index/Create.php

@@ -82,7 +82,7 @@ public function execute()
 
             $backupManager->create();
 
-            $this->messageManager->addSuccess($successMessage);
+            $this->messageManager->addSuccessMessage($successMessage);
 
             $response->setRedirectUrl($this->getUrl('*/*/index'));
         } catch (\Magento\Framework\Backup\Exception\NotEnoughFreeSpace $e) {

app/code/Magento/Backup/Controller/Adminhtml/Index/MassDelete.php

@@ -49,13 +49,13 @@ public function execute()
 
             $resultData->setIsSuccess(true);
             if ($allBackupsDeleted) {
-                $this->messageManager->addSuccess(__('You deleted the selected backup(s).'));
+                $this->messageManager->addSuccessMessage(__('You deleted the selected backup(s).'));
             } else {
                 throw new \Exception($deleteFailMessage);
             }
         } catch (\Exception $e) {
             $resultData->setIsSuccess(false);
-            $this->messageManager->addError($deleteFailMessage);
+            $this->messageManager->addErrorMessage($deleteFailMessage);
         }
 
         return $this->_redirect('backup/*/index');