We need to restore logging after calling the cli tools. Centralize
the logging reset behavior since we need that too
Signed-off-by: Cole Robinson <crobinso@redhat.com>
Init a shared log instance in virtinst/logger.py, and use that
throughout the code base, so we aren't calling directly into
'logging'. This helps protect our logging output from being
cluttered with other library output, as happens with some
'requests' usage