config.nonet does not exist

Which version of mojo, Ubuntu and lxc are you running?

mojo 0.4.1-2

host: xenial, mojo -c lxc

the buildphase force to use nonet config but it wasn't created.

class BuildPhase(ScriptPhase):
    """Execute a build script within a build directory. The build environment
       is restricted to have no access to networks.
       Arguments:
           config Base name for build script file
    """
    name = "build"

    def run(self, project, workspace, stage, auto_secrets=True):
        "Run a build script"
        # XXX: Remove network access during build phase
        super(BuildPhase, self).run(project, workspace, stage,
                                    lxc=True, network=False,
                                    auto_secrets=auto_secrets,
                                    gather_debug_logs=False)

In mojo/contain.py,
for xenial host, it didn't do the setup check just return true.
it skip the container.setup() to create /var/lib/lxc/{}/config.nonet and config.virtnet

class LXCContainer(Container):

    ...

    def is_setup(self):
        if UBUNTU_RELEASES.get(self.series) >= UBUNTU_RELEASES['vivid']:
            return True
        setup_file = self.container_root + "/etc/init/setup-stopped.conf"
        return os.path.exists(setup_file)

I'm also seeing this.
Ubuntu 16.10
LXD/LXC 2.4.1
Mojo 0.4.1 (from stable PPA)
Juju 2.0.2-yakkety-amd64 (from stable PPA)

Adding "build" to a manifest file, and creating a simple bash script names "build" is enough to trigger this behaviour.
Removing the "build" step in the manifest allows Mojo to continue.

Just to confirm this bug is still present in mojo 0.4.5

This has been fixed in 0.4.5-14