OPENJPA-2305: Canonical MetaModel class generation should not use inhertence - back-ported to 2.2.x Pinaki Poddar's commit to trunk.

git-svn-id: https://svn.apache.org/repos/asf/openjpa/branches/2.2.x@1476467 13f79535-47bb-0310-9956-ffa450edef68