Module novaclient.v1_1 is already deprecated, so it's time to stop using it
inside novaclient.
Since support of v3 nova is undocumented feature, which uses v2
implementation, we can remove code related to it.
Also, this patch removes redundant check for compute api version != 1.0.
Change-Id: I06b349f704d5ae2c592d8d286da268870f2a69e9