Fixes a typo introduced at r1553887 for "NPE thrown out while rendering disabled menu item" https://issues.apache.org/jira/browse/OFBIZ-5451
Spotted by Olivier

git-svn-id: https://svn.apache.org/repos/asf/ofbiz/trunk@1557185 13f79535-47bb-0310-9956-ffa450edef68