Congress tempest tests use wrong skip method

[Ghanshyam Mann]

Congress tempest scenario tests use "check_preconditions" method to define the class level skip condition. This method has been changed long back in Tempest.

Now skip condition goes to skip_checks(). Each tests class can add skip condition in skip_checks method to skip tests at class level- https://github.com/openstack/tempest/blob/master/tempest/test.py#L317

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/246871

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/246871
Committed: https://git.openstack.org/cgit/openstack/congress/commit/?id=c3204061a89122787369719545c20e04d56e3455
Submitter: Jenkins
Branch: master

commit c3204061a89122787369719545c20e04d56e3455
Author: Anusha Ramineni <email address hidden>
Date: Wed Nov 18 14:56:48 2015 +0530

    Use skip_checks to define class level skip condition

    check_preconditions() method is no longer available in tempest.
    So, this commit is to use skip_checks to define class level
    skip conditions

    Closes-Bug:#1517329
    Change-Id: I5d09da7416c040c57731cc8ea3ab519111834fab