Checkbox-cli crashes due to local variable 'configs' referenced before assignment

[Sylvain Pineau]

After the fix for absolute paths in configs it seems we broke checkbox-cli (result from a fresh install on a 16.04 system using the dev ppa):

$ checkbox-cli
Traceback (most recent call last):
  File "/usr/bin/checkbox-cli", line 800, in <module>
    CheckboxLauncher().main()
  File "/usr/bin/checkbox-cli", line 175, in main
    return CheckboxCommandRecipe(self).main(argv, exit)
  File "/usr/lib/python3/dist-packages/guacamole/recipes/__init__.py", line 119, in main
    retval = bowl.eat(argv)
  File "/usr/lib/python3/dist-packages/guacamole/core.py", line 236, in eat
    self._late_init()
  File "/usr/lib/python3/dist-packages/guacamole/core.py", line 293, in _late_init
    ingredient.late_init(self.context)
  File "/usr/bin/checkbox-cli", line 128, in late_init
    launcher.read(configs)
UnboundLocalError: local variable 'configs' referenced before assignment

$ dpkg --list "*checkbox*" "*plainbox*"
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-=====================================-=======================-=======================-================================================================================
un checkbox <none> <none> (no description available)
ii checkbox-converged 1.2.4-0ubuntu1 all testing tool for all Ubuntu devices
ii checkbox-gui 1.2.4-0ubuntu1 all QML based interface for checkbox (transitional package)
ii checkbox-ng 0.26+bzr4332+pkg39~ubun all PlainBox based test runner
ii plainbox 0.28+bzr4332+pkg42~ubun all toolkit for software and hardware integration testing
un plainbox-insecure-policy <none> <none> (no description available)
ii plainbox-provider-checkbox 0.25-1 amd64 CheckBox provider for PlainBox
ii plainbox-provider-resource-generic 0.23-1 amd64 CheckBox generic resource jobs provider
ii plainbox-secure-policy 0.28+bzr4332+pkg42~ubun all policykit policy required to use plainbox (secure version)
ii python3-checkbox-ng 0.26+bzr4332+pkg39~ubun all PlainBox based test runner (Python 3 library)
ii python3-checkbox-support 0.26+bzr4332+pkg28~ubun all collection of Python modules used by PlainBox providers
ii python3-plainbox 0.28+bzr4332+pkg42~ubun all toolkit for software and hardware testing (python3 module)