Do not ignore path deletion errors

Log as warning when an attempt to remove a directory
fails. This helps troubleshooting some bugs like the GC leaving
behind empty directories.

Change-Id: Idb94ce17f8be9668a970c7ecae31436bf434073c
Signed-off-by: Luca Milanesio <luca.milanesio@gmail.com>

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java

@@ -63,6 +63,7 @@ import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.nio.file.Files;
 import java.security.DigestInputStream;
 import java.security.MessageDigest;
 import java.text.MessageFormat;
@@ -1090,8 +1091,11 @@ public class RefDirectory extends RefDatabase {
 		}
 		File dir = file.getParentFile();
 		for (int i = 0; i < depth; ++i) {
-			if (!dir.delete()) {
-				break; // ignore problem here
+			try {
+				Files.delete(dir.toPath());
+			} catch (IOException e) {
+				LOG.warn("Unable to remove path {}", dir, e);
+				break;
 			}
 			dir = dir.getParentFile();
 		}