Fix test classes name of test_tokens.py

These test classes 'UsersTestJSON' and 'UsersTestXML' were introduced
for testing tokens in
  Change-Id: I9a810844b1d991f829f411db308e37a02bd6c09e
But their names are not suitable for their responsibility.
This commit fixes it.

Change-Id: I2bb51fe147c17846d667be6f259f63dcaeffe3fc
Prepare for enabling H302 (identity,volume,etc.)

We can use H302 rule but ignore it now. This commit prepares for
enabling H302 rule. But this commit modifies tempest/api/{identity,
orchestration, volume, utils} only and excludes some violations[1]
because if we fix all of them at one time, it's hard to merge this
commit.

[1]
 tempest.test.attr
 tempest.common.rest_client.RestClient
 tempest.common.rest_client.RestClientXML
 tempest.services.compute.xml.common.xml_to_json
 tempest.services.compute.xml.common.Element
 tempest.services.compute.xml.common.Document
 tempest.services.compute.xml.common.Text
 tempest.services.compute.xml.common.XMLNS_11
 tempest.services.compute.xml.common.XMLNS_V3
 tempest/clients.py

Change-Id: I811144df35a5a4d9a256cfaba1dcd28bbfbccb27
Merge "Prepare for enabling H302 (identity,volume,etc.)"
Merge "Fix test classes name of test_tokens.py"