tests/acceptance: allow console interaction with specific VMs

tests/acceptance: allow console interaction with specific VMs

Console interaction in avocado scripts was possible only with single
default VM.
This patch modifies the function parameters to allow passing a specific
VM as a parameter to interact with it.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <159073587933.20809.5122618715976660635.stgit@pasha-ThinkPad-X280>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
(cherry picked from commit a5ba86d423c2b071894d86c60487f2317c7ffb60)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>