Fixed bug reported by Christian Carlow in OFBIZ-5599: Facility Pick Stock Moves "Cannot compare: r-value is null" error when ProductFacilityLocation.minimumStock is not set.


git-svn-id: https://svn.apache.org/repos/asf/ofbiz/trunk@1609406 13f79535-47bb-0310-9956-ffa450edef68