Fixed typo in UI.

src/UI/Settings/MediaManagement/MediaManagementSettingsModel.js

@@ -3,5 +3,5 @@ var SettingsModelBase = require('../SettingsModelBase');
 module.exports = SettingsModelBase.extend({
     url            : window.NzbDrone.ApiRoot + '/config/mediamanagement',
     successMessage : 'Media management settings saved',
-    errorMessage   : 'Failed to save media managemnent settings'
+    errorMessage   : 'Failed to save media management settings'
 });