Comment 1 for bug 785542

This is now fix-committed, since revision 403 of trunk.

If you do not want 'nobootwait', then you will need to supply config (in /etc/cloud.cfg, or in /etc/cloud.cfg.d/<file>) that specifies a 'mount_default_fields'. Something like:
 mount_default_fields: [ None, None, "auto", "defaults,nofail", "0", "2" ]