avocado.plugins.vm: Adapt to test state

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
avocado.result: Fix docstring

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
selftests: Fix all unittests to use test state

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
tests: Add abort test

This calls os.abort() as the test action, testing avocado
ability of handle this case correctly.

Signed-off-by: Ruda Moura <rmoura@redhat.com>
avocado.job: Log a better error message on abort

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
selftests/functional: Add abort error to suite of functional tests

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>