Run nailgun tests in parallel in CI

[Aleksey Kasatkin]

Now we have ability to run nailgun tests in parallel but this ability is not in use within our CI.
We need to run these tests in parallel as it is the longest part of tests that is executed for fuel-web requests in CI.

[Dima Shulyak (dshulyak)]

Please check this patch for information on how to configure fuel-web/run_tests.sh to work in isolated environments.
https://review.openstack.org/#/c/104535/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/133257
Committed: https://git.openstack.org/cgit/stackforge/fuel-web/commit/?id=6b01a6c7d2f1c2f76b5f3164d95680d8fa5e0303
Submitter: Jenkins
Branch: master

commit 6b01a6c7d2f1c2f76b5f3164d95680d8fa5e0303
Author: Dima Shulyak <email address hidden>
Date: Fri Nov 7 17:01:18 2014 +0200

    Parallel test execution with py.test

    Patch adds ability to execute test run distributed over
    several processes, each one with isolated database.

    Assumptions:
    - nailgun user, requires createdb permission, if not please precreate
      databases in format described below
    - postgres database will be used for initial connection
    - for environment where createdb can not be granted, like ci
      operator need to create several databases, nailgun[0-7],
      count of databases should be equal to TEST_WORKERS variable
    - If no TEST_WORKERS provided - default database name will be used,
      it is almost every time nailgun, but you can overwrite it with
      TEST_NAILGUN_DB env variable

    To execute tests on your local environment:
      py.test -n 4 nailgun/tests/

    DocImpact
    Partial-Bug: 1388751
    Change-Id: I6037108f1888b61f971a10db5209b20712467173

[Igor Belikov (ibelikov)]

Test are running using 4 threads for a couple of days now.