This fixes a "bug" where polybar wouldn't reload on a configuration
file change on some configurations of vim, which don't actually issue
any IN_MODIFY events because they choose to move the file, replace it
with a new one, and then delete the file instead.
To work around this, we now also listen for IN_IGNORED which fires when
the file we are watching is destroyed. When this happens, we re-attach
the configuration file watcher to the new file and reload.
