'nova_version' should be str type
'nova_version' should be str type

Change-Id: I73ae7a30fa913e6ef0acc6ff2ca8ea62e493aae1
Signed-off-by: dongwenjuan <648f677d6c1326e8822df97fbbc7d15228521866@zte.com.cn>

openstack/vitrage,openstack/vitrage,openstack/vitrage