DERBY-5615(NPE in Store when running SELECT in a read-only database accessed via the classpath subprotocol when authentication, authorization, and Java security are turned on)

Backporting to 10.10



git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/branches/10.10@1639031 13f79535-47bb-0310-9956-ffa450edef68