DERBY-6630: Reduce visibility of JCECipherFactory and protect it with the usederbyinternals permission; tests passed cleanly on derby-6630-01-aa-usederbyinternals.diff.

git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1628206 13f79535-47bb-0310-9956-ffa450edef68