deploying branch-source-builder fails: charmhelpers.fetch.UnhandledSource:

I set up juju-local and deployed uci-engine as per http://uci.readthedocs.org/en/latest/using-lxc-for-local-development.html (although without modifying the LXC template container -- that's a really bad and wrong thing to do). I finally got the deployment to (mostly) run, but there's an error in the charm hook:

$ juju-deployer/deploy.py --working-dir /tmp/workdir/ branch-source-builder
Checking juju status
Private PPAs: disabled
Running juju-deployer -v -c /tmp/workdir/branch-source-builder.yaml ci-airline
2014-09-09 15:11:14 Using runtime GoEnvironment on local
2014-09-09 15:11:14 Starting deployment of ci-airline
2014-09-09 15:11:14 Connected to environment
2014-09-09 15:11:14 Getting charms...
2014-09-09 15:11:18 Resolving configuration
2014-09-09 15:11:18 Deploying services...
2014-09-09 15:11:18 <deployer.env.go.GoEnvironment object at 0x7f807513ead0>
2014-09-09 15:11:18 Deploying service ci-airline-bsb-keys using local:precise/key-secret-subordinate
2014-09-09 15:11:20 Deploying service ci-airline-bsb-worker using local:precise/rabbitmq-worker
2014-09-09 15:11:23 Deploying service ci-airline-rabbit using local:precise/rabbitmq-server
2014-09-09 15:11:32 Adding units...
2014-09-09 15:11:32 Config specifies num units for subordinate: ci-airline-bsb-keys
2014-09-09 15:11:32 Service 'ci-airline-bsb-worker' does not need any more units added.
2014-09-09 15:11:32 Service 'ci-airline-rabbit' does not need any more units added.
2014-09-09 15:11:32 Waiting for units before adding relations
2014-09-09 15:13:38 The following units had errors:
   unit: ci-airline-bsb-worker/0: machine: 1 agent-state: error details: hook failed: "config-changed"
2014-09-09 15:13:38 Deployment stopped. run time: 144.32
Problem deploying "ci-airline": Command '['juju-deployer', '-v', '-c', '/tmp/workdir/branch-source-builder.yaml', 'ci-airline']' returned non-zero exit status 1

$ juju status
environment: local
machines:
  "0":
    agent-state: started
    agent-version: 1.20.5.1
    dns-name: localhost
    instance-id: localhost
    series: utopic
    state-server-member-status: has-vote
  "1":
    agent-state: started
    agent-version: 1.20.5.1
    dns-name: 10.0.3.58
    instance-id: martin-local-machine-1
    series: precise
    hardware: arch=amd64
  "2":
    agent-state: started
    agent-version: 1.20.5.1
    dns-name: 10.0.3.53
    instance-id: martin-local-machine-2
    series: precise
    hardware: arch=amd64
services:
  ci-airline-bsb-keys:
    charm: local:precise/key-secret-subordinate-1
    exposed: false
  ci-airline-bsb-worker:
    charm: local:precise/rabbitmq-worker-0
    exposed: false
    units:
      ci-airline-bsb-worker/0:
        agent-state: error
        agent-state-info: 'hook failed: "config-changed"'
        agent-version: 1.20.5.1
        machine: "1"
        public-address: 10.0.3.58
  ci-airline-rabbit:
    charm: local:precise/rabbitmq-server-98
    exposed: false
    relations:
      cluster:
      - ci-airline-rabbit
    units:
      ci-airline-rabbit/0:
        agent-state: started
        agent-version: 1.20.5.1
        machine: "2"
        open-ports:
        - 5672/tcp
        - 55672/tcp
        public-address: 10.0.3.53

The charm log ends with this (I'll attach the full log for reference):

2014-09-09 13:13:35 INFO config-changed Setting up python-bzrlib (2.5.1-0ubuntu2) ...
2014-09-09 13:13:36 INFO juju-log Making dir /var/lib/juju/agents/unit-ci-airline-bsb-worker-0/charm/fetched root:root 755
2014-09-09 13:13:36 INFO config-changed Traceback (most recent call last):
2014-09-09 13:13:36 INFO config-changed File "/var/lib/juju/agents/unit-ci-airline-bsb-worker-0/charm/hooks/config-changed", line 398, in <module>
2014-09-09 13:13:36 INFO config-changed hooks.execute(sys.argv)
2014-09-09 13:13:36 INFO config-changed File "/var/lib/juju/agents/unit-ci-airline-bsb-worker-0/charm/hooks/charmhelpers/core/hookenv.py", line 480, in execute
2014-09-09 13:13:36 INFO config-changed self._hooks[hook_name]()
2014-09-09 13:13:36 INFO config-changed File "/var/lib/juju/agents/unit-ci-airline-bsb-worker-0/charm/hooks/config-changed", line 265, in config_changed
2014-09-09 13:13:36 INFO config-changed todelete = handle_code()
2014-09-09 13:13:36 INFO config-changed File "/var/lib/juju/agents/unit-ci-airline-bsb-worker-0/charm/hooks/config-changed", line 124, in handle_code
2014-09-09 13:13:36 INFO config-changed _payload_extract(payload)
2014-09-09 13:13:36 INFO config-changed File "/var/lib/juju/agents/unit-ci-airline-bsb-worker-0/charm/hooks/config-changed", line 94, in _payload_extract
2014-09-09 13:13:36 INFO config-changed src = charmhelpers.fetch.install_remote(payload)
2014-09-09 13:13:36 INFO config-changed File "/var/lib/juju/agents/unit-ci-airline-bsb-worker-0/charm/hooks/charmhelpers/fetch/__init__.py", line 333, in install_remote
2014-09-09 13:13:36 INFO config-changed raise UnhandledSource("No handler found for source {}".format(source))
2014-09-09 13:13:36 INFO config-changed charmhelpers.fetch.UnhandledSource: No handler found for source http://10.0.3.134:8080/v1/AUTH_testproj/ci-payload/fdf2538760d0c4b5bb716b6b4a2d84d2704a3760.tgz
2014-09-09 13:13:36 ERROR juju.worker.uniter uniter.go:486 hook failed: exit status 1