Comment 15 for bug 1541309

Reviewed: https://review.openstack.org/322753
Committed: https://git.openstack.org/cgit/openstack/fuel-web/commit/?id=8de9381d4877fc208214c1878eca037d3b7594a0
Submitter: Jenkins
Branch: stable/mitaka

commit 8de9381d4877fc208214c1878eca037d3b7594a0
Author: Igor Kalnitsky <email address hidden>
Date: Wed May 25 12:19:22 2016 +0300

    Allow YAQL expressions in task's dependencies

    Since Fuel 9.0 we have a task-based deployment turned on by default.
    That means our tasks are executing simultaneously on several nodes, and
    old static approach for specifying dependencies doesn't work anymore.

    In order to avoid dependency loops and make possible to rely on
    different tasks based on some condition, we've got to be able to
    calculate `cross-depends` and `cross-depended-by` attributes on fly.

    Fortunately, we already have traversal mechanism that evaluates YAQL
    expressions almost everywhere. So all we need to do is to remove
    validation limitation and allow to upload deployment tasks with YAQL
    expressions in those fields.

    (cherry picked from commit 886ab3087c0eb348e9b88090d69bf462a3e50962)

    Change-Id: I393dfb06f9e25ecd3ca79fddc84104a8cf993094
    Partial-Bug: #1541309