Tab bar is unnecessary in detail pages with a single tab

[Akihiro Motoki]

Tab bar is used even when a detail page has only one tab. It is unnecessary.

Tab styling is now improved in https://review.openstack.org/#/c/128247/ and once this is merged, the tab bar in a detail page with a single tab maybe be a bit surprising.

Red square in the attached image is an example.
(Note that Blue square in the image is a different issue but it needs to be improved too.)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/129449

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/129449
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=4668dc4548e72accefe8d08c0de547fb8709c544
Submitter: Jenkins
Branch: master

commit 4668dc4548e72accefe8d08c0de547fb8709c544
Author: Akihiro Motoki <email address hidden>
Date: Mon Oct 20 06:55:54 2014 +0900

    Allow to hide tab title bar when only one tab is available

    In detail pages with a single tab, tab title bars are redundant
    and unnecessary. For such pages, it would be nice if a tab bar
    is hidden.

    This commit introduces show_single_tab attribute to TabGroup
    class. The default value is set to False because hiding a tab bar
    for a single tab page looks appropriate in most cases.

    Tab mechanism makes developers to add new tabs for extensibility.
    If we remove tab view and change such view into a normal DetailView
    we will lose the extensibility. After discussion with some Horizon
    developers, it sounds nice to hide tab bar for a single tab page.

    Closes-Bug: #1382546
    Change-Id: I90276c531d0a017e3970b48290ae730ea3f1ecad