regular user cannot clear gateway of a quantum router

[Akihiro Motoki]

A regular user cannot "Clear gateway" since a router gateway interface is not displayed in a list of router interfaces.

In addition, router detail panel has "Add gateway" button, but there is no information about router gateway is set or not due to the same reason above.

I would like to propose the following changes:
- Display "external gateway info" in router detail panel (below admin state)
- Move "Add Gateway Interface" to router table. It comes from the following reasons:
-- Gateway interface cannot be displayed in a router interface list since router gateway interface is intentionally hidden from a regular user (by quantum)
-- Gateway configuration is a operation per router rather than per interface.

In G-3 milestone, quantum made a change to allow regular users to set non-owned external network as router gateway.
When Horizon Quantum router support was implemented, this change has not been merged, we cannot test "Add gateway interface" with non-admin user. That is the reason of this bug.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/23477

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/23477
Committed: http://github.com/openstack/horizon/commit/c97e693a9dd36ff1742afcbba306ca84f6394df8
Submitter: Jenkins
Branch: master

commit c97e693a9dd36ff1742afcbba306ca84f6394df8
Author: Akihiro MOTOKI <email address hidden>
Date: Fri Feb 22 02:35:59 2013 +0900

    Allow non-admin users to clear router gateway properly

    Fixes bug 1131193

    In Grizzly-3 milestone, quantum made a change to allow regular users
    to set non-owned external network as router gateway, but Quantum
    router support cannot handle it, particularily non-admin user cannot
    clear router gateway. This means non-admin cannot delete a router as
    a result. In addition, there is no way for non-admin users to check
    if router gateway is set or not since a non-admin user cannot see
    a router gateway.

    To address the above issues, this commit does the following changes:
    - Display "external gateway info" in router table and detail to allow
      non-admin users to check if a router is connected to an external
      network (i.e., a router has a default gateway).
    - Move "Set/Clear Gateway" button to router table and Set/Clear
      button is displayed based on an existence of router gateway.
    - Move "Set/Clear Gateway" button in Admin panel in the same way
      to keep consistency with Project panel.

    Change-Id: Ib096d5e40c88b8a605ad8aae26d1f5cf7fd745e6