MK8S-25: Enhance index.html cleanup to remove empty directories

Fix "Cleanup build tree" failures by ensuring clean functions remove
not just index.html files but also any empty parent directories created
during index file creation. This prevents directory removal conflicts
during the overall cleanup process.

- Clean up index.html files first
- Remove empty parent directories that were created for index files
- Use safe directory removal with OSError handling
- Ensures proper cleanup coordination between repository and packaging tasks

Author: rdebay-scality

buildchain/buildchain/targets/repository.py

@@ -273,10 +273,18 @@ def create_index_files(self) -> types.TaskDict:
 
         def clean() -> None:
             """Delete the index.html files created by this task."""
-            # Actually remove the index.html files
+            # Remove the index.html files
             for index_file in self._get_index_file_paths():
                 if index_file.exists():
                     index_file.unlink()
+            # Also clean up any empty parent directories that we created
+            for index_file in self._get_index_file_paths():
+                parent_dir = index_file.parent
+                if parent_dir.exists() and not any(parent_dir.iterdir()):
+                    try:
+                        parent_dir.rmdir()
+                    except OSError:
+                        pass  # Directory not empty or doesn't exist, ignore
 
         def create_index() -> None:
             """Create empty index.html files in repository directories."""