Error starting hosting-queued with Drush 8 on Ubuntu 14.04

Using the hosting_queued daemon with the development version of Drush (from 2015-10-28) does not work, attempting to run `sudo service hosting-queued start` (or `sudo /etc/init.d/hosting-queued start`) gives me this error:

Starting Aegir queue daemon... ok
liam@web1:/opt/drush$ /usr/local/bin/drush: 2: /usr/local/bin/drush: cannot open ?php: No such file
/usr/local/bin/drush: 4: /usr/local/bin/drush: /bin: Permission denied
/usr/local/bin/drush: 5: /usr/local/bin/drush: backups: not found
/usr/local/bin/drush: 6: /usr/local/bin/drush: backups: not found
/usr/local/bin/drush: 7: /usr/local/bin/drush: backups: not found
/usr/local/bin/drush: 8: /usr/local/bin/drush: Syntax error: word unexpected (expecting ")")

I have narrowed the problem down to line 30 of hosting-queued:

su - $USER -- $DAEMON $DAEMON_ARGS &

I expanded the variables manually and ran this (as root):

su - "aegir" -- /usr/local/bin/drush @hostmaster hosting-queued

Which yields the same error message as above. However, sudo-ing as the aegir user, then running `/usr/local/bin/drush @hostmaster hosting-queued` works, so this seems to be related to the usage of `su` and that the `drush` executable is now a PHP file instead of a Bash/sh script.