When the ptest distro feature is disabled, a ptest directory is still
created in the install phase, This directory is not cleaned up or
consumed by any package and will throw a QA error, e.g.
ERROR: QA Issue: glib-2.0: Files/directories were installed but not
shipped
/usr/lib/glib-2.0/ptest
ERROR: QA run found fatal errors. Please consider fixing them.
ERROR: Function failed: do_package_qa
This is caused by the do_install_ptest_base[cleandirs] attribute which
is not setup to be conditional on ptest being enabled.
This patch refactors the use of PTEST_ENABLED in the *ptest_base tasks,
replacing the conditional execution with the removal of the tasks from
the build, this prevents any part (including cleandirs) of the ptest
tasks from executing when disabled.
