fix: don't crash in cache refresh/update with nil fsnotify watcher.#254

bart0sh merged 3 commits intocncf-tags:maincncf-tags/container-device-interface:mainfrom

klihub:fixes/refresh-sigsegv-with-nil-watcherklihub/container-device-interface:fixes/refresh-sigsegv-with-nil-watcherCopy head branch name to clipboard