test-permissions: add a chmod +w to allow the directory to be removed

run-tests.py: don't print a dot for skipped tests

purge: simplify safety net for case mangling filesystems Relying on the exact return of statwalk would cause us to abort when there was at least one tracked file inside an ignored directory. This patch forces an extra walk of the whole working directory even on sane filesystems, where it wouldn't be needed. Fixes issue621.