Since tox_envlist has a default value it cannot be undefined
so the fail task will never run. Instead handle the case when
tox_envlist is an empty string by getting the default configured
envlist from tox. Also handle the casewhen tox_envlist is 'ALL'.
This also updates tox_install_sibling_packages to correctly
handle multiple testenvs and uses configuration supplied by
'tox --showconfig -e <envlist>' instead of guessing where the
envdir and logdir are located.
We also cannot run tox inside python because it gets complicated
to know which tox_executable we should call during the python test
cases so run these commands in ansible and pass the output to
tox_install_sibling_packages.
Since role params have higher precedence than set_fact we set an
internal _tox_envlist fact that is a comma separated list of testenvs
that should be run.
Change-Id: I9e5a1b041f653cbcff7b8ed62e4a95a0a040fdd7
86041d9914