Previously the os_tempest role had a single variable for
defining the include and exclude lists in order to select the
tempest tests to run.
This works for simple scenarios, where a single service
is deployed and the tests for that service are enabled through
the necessary variables set in user_variables. This approach is
used in openstack-ansible CI / AIO.
More complicated scenarios such as magnum+barbican+octavia, would
create several user_variables files each with conflicting settings
for the test settings. It is possible in this scenario for there to
be no valid tempest tests to run and tempest to fail immediately.
This patch adds the possibility to have many variables defining
the include/exclude lists which have names using a common prefix.
Any variable names matching the prefix are gathered and combined
with the original role default to make extending the test lists
easy to do in an incremental/distibuted way in the ansible variables
instead of having to maintain a single point defining all necessary
tests.
Change-Id: Ie3a9a7be849171af042567ba8a152e5df5d2cb53
242203bafa