DERBY-6562: Failed to delete directory in LuceneSupportPermsTest.test_005_deleteDirectory()

The test should look for the "LUCENE" subdirectory rather than the
"lucene" subdirectory.

git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1592464 13f79535-47bb-0310-9956-ffa450edef68