The full testing of the leapp framework requires installation of the
leapp-repository builds to perform the in-place upgrade. Setting
the `INSTALL_LEAPP_FROM_COMPOSE` envar to `yes` implicates installation
of the leapp-repository packages for the test execution.
Also set LEAPP_UNSUPPORTED and LEAPP_DEVEL_* envars to be able
to perform upgrade also with old builds on the wanted new upgrade
path. We are going to resolve this in future.
The original tier0 test plans have been replaced by "new style" tests
and the original plans do not exist anymore. Updating so the tier0
test can be executed correctly.
