Make working en_US.UTF-8 locale a hard requirement

lib/base.php

@@ -241,7 +241,7 @@ class OC {
 					$minimizerCSS->clearCache();
 					$minimizerJS = new OC_Minimizer_JS();
 					$minimizerJS->clearCache();
-					OC_Util::addscript('update');
+					OC_Util::addScript('update');
 					$tmpl = new OC_Template('', 'update.admin', 'guest');
 					$tmpl->assign('version', OC_Util::getVersionString());
 					$tmpl->printPage();
@@ -564,12 +564,6 @@ class OC {
 			}
 		}
 
-		// write error into log if locale can't be set
-		if (OC_Util::isSetLocaleWorking() == false) {
-			OC_Log::write('core',
-				'setting locale to en_US.UTF-8/en_US.UTF8 failed. Support is probably not installed on your system',
-				OC_Log::ERROR);
-		}
 		if (OC_Config::getValue('installed', false) && !self::checkUpgrade(false)) {
 			if (OC_Appconfig::getValue('core', 'backgroundjobs_mode', 'ajax') == 'ajax') {
 				OC_Util::addScript('backgroundjobs');

lib/private/util.php

@@ -353,6 +353,13 @@ class OC_Util {
 			$errors = array_merge($errors, self::checkDataDirectoryPermissions($CONFIG_DATADIRECTORY));
 		}
 
+		if(!OC_Util::isSetLocaleWorking()) {
+			$errors[] = array(
+				'error' => 'Setting locale to en_US.UTF-8/en_US.UTF8 failed',
+				'hint' => 'Please install the locale on your system and restart your webserver.'
+			);
+		}
+
 		$moduleHint = "Please ask your server administrator to install the module.";
 		// check if all required php modules are present
 		if(!class_exists('ZipArchive')) {