Root API is not showing version information

[Dimitri Mazmanov]

When the user hits http://serv_api:8118 instead of version information kingbird returns 401 authentication error.
This is not correct behavior, since the expectation is to get info about supported versions.

The issue is related to outdated code in API. We need to rewrite how we attach version controllers.
Refactoring of the API part is needed to fix the issue and also clean up the code.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/447892

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/447892
Committed: https://git.openstack.org/cgit/openstack/kingbird/commit/?id=8e0acbdcc5afe92d41777c251a8c2ec973649532
Submitter: Jenkins
Branch: master

commit 8e0acbdcc5afe92d41777c251a8c2ec973649532
Author: Goutham Pratapa <email address hidden>
Date: Tue Mar 21 12:18:57 2017 +0530

    Fix to show version information from root API.

    When the user hits http://serv_api:8118 instead of version information
    kingbird returns 401 authentication.Introduced a new section
    pecan configurations and pecan hooks to fix this error.
    Added test-cases, made trivial changes for tempest tests and refactored
    some code.

    Closes-Bug: #1673383
    Change-Id: Ic87b078a73bd0505b309f099cffdfb7ee31ba8e3