ybd no longer supports recursive submodules...

as discussed at https://irclogs.baserock.org/%23baserock.2016-09-30.log.html#t2016-09-30T14:49:34 and again at https://irclogs.baserock.org/%23baserock.2016-10-06.log.html#t2016-10-06T09:43:18

the offending commit appears to be 4072533d