GTNWSRP-350: prefer export by value and only use export by reference when we have set an ExportPersistenceManager and don't prefer export by value.
(cherry-picked from f8a32cf)
GTNWSRP-353: use default locale if we're dealing with a preference that wasn't set in portlet.xml since JSR-286 doesn't forbid setting such preferences.
(cherry picked from commit 1f9d800)