remove unused import

Author: vladak

opengrok-indexer/src/test/java/org/opengrok/indexer/history/FileHistoryCacheTest.java

@@ -38,7 +38,6 @@
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
-import java.net.URI;
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;