sanitytest: move initial class method mapping into a helper method
sanitytest: move initial class method mapping into a helper method

This is a step towards turning the sanitytest.py file into a normal
python unittest.

Best viewed with the '-b' flag to diff.

Signed-off-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

libvirt/libvirt-python,libvirt/libvirt-python,libvirt/libvirt-python