This commit makes sure that the Python list vms_list is not mutated
while the code is iterating through it. To the best of my knowledge,
this is a problematic operation.
To rectify this issue, a new temporary list is instantiated, and
the VM objects that have shut down are appended to the temporary list,
which is afterwards used to remove the shut-down VM objects from the
vms_list.
Signed-off-by: M. Vefa Bicakci <m.v.b@runbox.com>
6bcc97b859