Fixes an issue reported by Christian Carlow at "Invoice Item type drop down empty when creating new invoice item" https://issues.apache.org/jira/browse/OFBIZ-5415

jleroux: Rather than what proposed Christian I used the same best practice than in r1527171

git-svn-id: https://svn.apache.org/repos/asf/ofbiz/trunk@1547717 13f79535-47bb-0310-9956-ffa450edef68