Commit 15f82c7 ("used pyinotify as change detection system when
available") introduced a regression where editing a file in vim with
default settings (writebackup=auto) no longer causes the dev server
to be restarted. On a write, vim moves the monitored file to a backup
path and then creates a new file in the original. The new file is not
monitored as it has a different inode. Fixed this by also watching for
inotify events IN_DELETE_SELF and IN_MOVE_SELF.
Backport of e5cfa394d79b6ab1b412bd3b30c6a433b415d56b from master