Config file must be writable during upgrade so that plugins are successfully activated/deactivated

otherwise Piwik can be left in a state where a warning is displayed and it's hard to troubleshoot that config is only mentionned in config file

core/Updates/3.0.0-b1.php

@@ -68,11 +68,8 @@ class Updates_3_0_0_b1 extends Updates
         ServerFilesGenerator::createHtAccessFiles();
 
         // Renamed plugin ExampleRssWidget -> RssWidget
-        try {
-            \Piwik\Plugin\Manager::getInstance()->activatePlugin('RssWidget');
-            \Piwik\Plugin\Manager::getInstance()->deactivatePlugin('ExampleRssWidget');
-        } catch (\Exception $e) {
-        }
+        \Piwik\Plugin\Manager::getInstance()->activatePlugin('RssWidget');
+        \Piwik\Plugin\Manager::getInstance()->deactivatePlugin('ExampleRssWidget');
     }
 
     private function migratePluginEmailUpdateSetting()