Add config feature verification script

This commit adds a new tool to tempest that will verify that API
queryable config options are set correctly. Right now the list of
options that are verified is very short. Later on additional checks
will be added to verify other services features when the tempest
clients for the other services get functions to query enabled
extensions.

Partially Implements: blueprint config-verification

Change-Id: Ie3b5fadd74460fb7199bff7046ec0efe37268b94
Add api version detection to verify_tempest_config

This commit adds glance api version discovery to
verify_tempest_config.py. It will query the glance API to see which
API versions are available and then compare that to what is in the
config, pointing out any differences

Partially Implements: blueprint config-verification

Change-Id: Ie75f7f526d78b85a53ea4b0484e670d373d622ec
Fix incorrect config option types

This commit just fixes a few option types to that were incorrectly set.

Partially Implements: blueprint config-cleanup

Change-Id: I12c743f85b35ea1d1f8df92c988c141c78c2730d
Fix default values so they work in a devstack run

This commit fixes errors with the default values used in config.py
Previously, an incorrect default could potentially be masked in a
gate run by putting the correct value in the sample config. However,
by moving to an auto-generated sample config file the defaults set
in config.py will be used, exposing these mismatches.

Partially Implements: blueprint config-cleanup

Change-Id: I55caeed2589d45337337b291d7131afdadf28bb8
Merge "Add config feature verification script"
Merge "Add api version detection to verify_tempest_config"
Merge "Fix incorrect config option types"
Merge "Fix default values so they work in a devstack run"