DERBY-6662; DatabaseMetaData.usesLocalFiles() returns true for in-memory databases
   Making the usesLocalFiles and usesLocalFilePerTable method return false if it's a memory database and add a test.


git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1627671 13f79535-47bb-0310-9956-ffa450edef68