novaclient.v1_1 has been deprecated and moved to v2 since v2.21.0,
a warning message will be printed if we still use it:
UserWarning: Module novaclient.v1_1 is deprecated (taken as a
basis for novaclient.v2). The preferable way to get client class
or object you can find in novaclient.client module.
This patch uses novaclient.client.Client and specifies version=2
to replace old novaclient.v1_1.client.Client
Change-Id: I0155caaa63b670f9b37c91e2297bd6b988784bf7