(PECL inotify >= 0.1.2)
inotify_rm_watch — Remove an existing watch from an inotify instance
$inotify_instance, int $watch_descriptor): bool
inotify_rm_watch() removes the watch
watch_descriptor from the inotify instance
inotify_instance.
成功时返回 true， 或者在失败时返回 false。