Do not setUpClass or tearDownClass V3 tests if API is disabled

Bugs in performing tearDown may occur if v3 is
disabled as the skip would cause the setUp to be
incomplete, causing the tearDown to reference undefined
instance variables.

Change-Id: I69110c6149ee22aa3e0d6ee27c52ef0159e9a235
Closes-Bug: #1282839
Closes-Bug: #1282829
Closes-Bug: #1282827
Enable H302 check (tempest/services/volume)

We can use H302 rule but ignore it now. This commit prepares for
enabling H302 rule. But this commit modifies a part of Tempest only
because if we fix all of them at one time, it's hard to merge this
commit.
    ---------------
    tempest/api/compute/admin
    tempest/api/compute/{c*,f*,i*,s*,t*}
    tempest/api/compute/{v3,volumes},data_processing
    tempest/api/identity/admin
    tempest/api/image
    tempest/api/{n*,o*,t*}
    tempest/api/volume,tempest/*
    tempest/services/compute/json
    tempest/services/compute/v3/json
    tempest/services/compute/xml
    tempest/services/identity
    tempest/services/{im*,n*,o*,t*}
    tempest/services/volume     <- This patch
    tempest/clients.py: TBD
    ---------------

Change-Id: Ifd170aa0c9f10e8af0d0e426cc6b3862030a443f
Merge "Enable H302 check (tempest/services/volume)"
Merge "Do not setUpClass or tearDownClass V3 tests if API is disabled"
Merge branch 'master' of https://github.com/openstack/tempest