Replace old config code with usage of proper APIs

apps/files_trashbin/tests/trashbin.php

 		//disable encryption
 		\OC_App::disable('encryption');
 
+		$config = \OC::$server->getConfig();
 		//configure trashbin
-		self::$rememberRetentionObligation = \OC_Config::getValue('trashbin_retention_obligation', Files_Trashbin\Expiration::DEFAULT_RETENTION_OBLIGATION);
-		\OC_Config::setValue('trashbin_retention_obligation', 'auto, 2');
+		self::$rememberRetentionObligation = $config->getSystemValue('trashbin_retention_obligation', Files_Trashbin\Expiration::DEFAULT_RETENTION_OBLIGATION);
+		$config->setSystemValue('trashbin_retention_obligation', 'auto, 2');
 
 		// register hooks
 		Files_Trashbin\Trashbin::registerHooks();
 		// cleanup test user
 		\OC_User::deleteUser(self::TEST_TRASHBIN_USER1);
 
-		\OC_Config::setValue('trashbin_retention_obligation', self::$rememberRetentionObligation);
+		\OC::$server->getConfig()->setSystemValue('trashbin_retention_obligation', self::$rememberRetentionObligation);
 
 		\OC_Hook::clear();
 

lib/private/installer.php

 		if (is_null($info)) {
 			return false;
 		}
-		\OC::$server->getAppConfig()->setValue($app, 'installed_version', OC_App::getAppVersion($app));
+
+		$config = \OC::$server->getConfig();
+
+		$config->setAppValue($app, 'installed_version', OC_App::getAppVersion($app));
 		if (array_key_exists('ocsid', $info)) {
-			\OC::$server->getAppConfig()->setValue($app, 'ocsid', $info['ocsid']);
+			$config->setAppValue($app, 'ocsid', $info['ocsid']);
 		}
 
 		//set remote/public handlers
 		foreach($info['remote'] as $name=>$path) {
-			OCP\CONFIG::setAppValue('core', 'remote_'.$name, $app.'/'.$path);
+			$config->setAppValue('core', 'remote_'.$name, $app.'/'.$path);
 		}
 		foreach($info['public'] as $name=>$path) {
-			OCP\CONFIG::setAppValue('core', 'public_'.$name, $app.'/'.$path);
+			$config->setAppValue('core', 'public_'.$name, $app.'/'.$path);
 		}
 
 		OC_App::setAppTypes($info['id']);
 	 */
 	public static function checkCode($folder) {
 		// is the code checker enabled?
-		if(!OC_Config::getValue('appcodechecker', false)) {
+		if(!\OC::$server->getConfig()->getSystemValue('appcodechecker', false)) {
 			return true;
 		}
 

lib/private/setup.php

 		$content.= "</ifModule>\n\n";
 		$content.= "# section for Apache 2.2 and 2.4\n";
 		$content.= "IndexIgnore *\n";
-		file_put_contents(\OC_Config::getValue('datadirectory', \OC::$SERVERROOT.'/data').'/.htaccess', $content);
-		file_put_contents(\OC_Config::getValue('datadirectory', \OC::$SERVERROOT.'/data').'/index.html', '');
+
+		$baseDir = \OC::$server->getConfig()->getSystemValue('datadirectory', \OC::$SERVERROOT . '/data');
+		file_put_contents($baseDir . '/.htaccess', $content);
+		file_put_contents($baseDir . '/index.html', '');
 	}
 }