dfs: Fix build break caused by DfsStreamKey.of signature change

Change-Id: I6c49cf42a04dd0d96cfe0751f500a51f56f0bdb8

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DeltaBaseCacheTest.java

@@ -63,7 +63,8 @@ public class DeltaBaseCacheTest {
 
 	@Before
 	public void setUp() {
-		key = DfsStreamKey.of("test.key");
+		DfsRepositoryDescription repo = new DfsRepositoryDescription("test");
+		key = DfsStreamKey.of(repo, "test.key");
 		cache = new DeltaBaseCache(SZ);
 		rng = new TestRng(getClass().getSimpleName());
 	}

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsBlockCache.java

@@ -178,7 +178,10 @@ public final class DfsBlockCache {
 		blockSizeShift = Integer.numberOfTrailingZeros(blockSize);
 
 		clockLock = new ReentrantLock(true /* fair */);
-		clockHand = new Ref<>(DfsStreamKey.of(""), -1, 0, null); //$NON-NLS-1$
+		String none = ""; //$NON-NLS-1$
+		clockHand = new Ref<>(
+				DfsStreamKey.of(new DfsRepositoryDescription(none), none),
+				-1, 0, null);
 		clockHand.next = clockHand;
 
 		statHit = new AtomicLong();