Error deploying charm on juju-core with CI options

[Nicola 'teknico' Larosa]

When using the charm to deploy a branch with these config changes on
juju-core, for testing CI:

juju-gui-source: lp:~teknico/juju-gui/fix-charm-panel-tests
staging: true
serve-tests: true
secure: false

$ juju bootstrap -e juju-gui-testing
$ JUJU_ENV=juju-gui-testing make deploy

the following error happens in the install hook:

2013/06/14 14:08:04 INFO juju-gui/0: >>> Entering install
2013/06/14 14:08:04 INFO worker/uniter/jujuc: running hook tool
  "juju-log" ["--" "Not a directory: exec.d/.empty/charm-pre-install"]
2013/06/14 14:08:04 DEBUG worker/uniter/jujuc: hook context id
  "juju-gui/0:install:4471045625928978785"; dir
  "/var/lib/juju/agents/unit-juju-gui-0/charm"
2013/06/14 14:08:04 INFO juju-gui/0: Not a directory:
  exec.d/.empty/charm-pre-install
2013/06/14 14:08:04 INFO worker/uniter/jujuc: running hook tool
  "config-get" ["--format" "json"]
2013/06/14 14:08:04 DEBUG worker/uniter/jujuc: hook context id
  "juju-gui/0:install:4471045625928978785";
  dir "/var/lib/juju/agents/unit-juju-gui-0/charm"
2013/06/14 14:08:04 INFO worker/uniter/jujuc: running hook tool
  "juju-log" ["--" "<<< Exiting install"]
2013/06/14 14:08:04 DEBUG worker/uniter/jujuc: hook context id
  "juju-gui/0:install:4471045625928978785";
  dir "/var/lib/juju/agents/unit-juju-gui-0/charm"
2013/06/14 14:08:04 INFO juju-gui/0: <<< Exiting install
2013/06/14 14:08:04 INFO worker/uniter: HOOK Traceback (most recent call
  last):
2013/06/14 14:08:04 INFO worker/uniter: HOOK   File
  "/var/lib/juju/agents/unit-juju-gui-0/charm/hooks/install", line 89,
  in <module>
2013/06/14 14:08:04 INFO worker/uniter: HOOK     main()
2013/06/14 14:08:04 INFO worker/uniter: HOOK   File
  "/var/lib/juju/agents/unit-juju-gui-0/charm/hooks/install", line 81,
  in main
2013/06/14 14:08:04 INFO worker/uniter: HOOK     backend =
  Backend(config)
2013/06/14 14:08:04 INFO worker/uniter: HOOK   File
  "/var/lib/juju/agents/unit-juju-gui-0/charm/hooks/backend.py", line
  191, in __init__
2013/06/14 14:08:04 INFO worker/uniter: HOOK     raise
  ValueError('Unable to use staging with go backend')
2013/06/14 14:08:04 INFO worker/uniter: HOOK ValueError: Unable to use
  staging with go backend
2013/06/14 14:08:04 ERROR worker/uniter: hook failed: exit status 1

Is anyone able to deploy with juju-core and staging enable?

-- 
Nicola 'teknico' Larosa <https://launchpad.net/~teknico>