GUACAMOLE-220: Convert "namespace" attribute of managementButtons directive to string binding.

guacamole/src/main/webapp/app/manage/templates/manageUser.html

@@ -65,7 +65,7 @@
         </connection-permission-editor>
 
         <!-- Form action buttons -->
-        <management-buttons namespace="'MANAGE_USER'"
+        <management-buttons namespace="MANAGE_USER"
               permissions="managementPermissions[dataSource]"
               save="saveUser()"
               delete="deleteUser()"