Applied hand merged bug fix changes from trunk r1647946.
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Applied patch from jira issue - OFBIZ-5385 - Purchase order immutable/unchangeable errors when adding variant products.
In this changes Arun has taken care of cloning related concern raised by Adrian. Thanks Arun for the contribution.
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git-svn-id: https://svn.apache.org/repos/asf/ofbiz/branches/release13.07@1647947 13f79535-47bb-0310-9956-ffa450edef68