fails to run with buildout cfg file in subdirectory

[Alexandre Fayolle - camptocamp]

I'm trying to configure the buildbot for our buildout setup. We use a directory structure as follows:

.
├── bootstrap.py
├── buildbot
│   ├── buildout.cfg
│   ├── openerp_customer.cfg
│   └── openerp_trunk_customer.cfg
└── official
│ ├── openerp_customer.cfg # extends ../../boostrap.cfg (not in the repo)
│ ├── openerp_prod_customer.cfg
│ ├── openerp_qa_customer.cfg
│ ├── openerp_test_customer.cfg
│ └── openerp_trunk_customer.cfg # extends openerp_customer.cfg
└── feature
    ├── openerp_customer.cfg
....

(the buildbot directory and bootstrap.py have been added. What we usually use is base buildout.cfg + bootstrap.cfg from a different repository (shared between projects)

[customer]
buildout = bzr lp:path_to_config buildbot/openerp_trunk_customer.cfg

When I do that, the bin/buildout file is generated in buildbot/ and then attempting to run bin/buildout fails (no such file or directory). I think a test should be added and if the path is in a subdirectory, the 'buildout:directory=explicit_path_to_root' argument should be passed on the command line