Solidify environment_version handling in run_tests.sh

[Doug Fish]

We've had a number of review problems/escaped bugs related to the handling of the environment_version in run_tests.sh.

The problem is that its an integer and it is supposed to increase sequentially. If there are multiple environment related patches out for review in parallel only the first one will update the environment_version. The others will have their environment_version successfully merge unless the developer or a reviewer noticed.

I plan to fix this by making the environment_version a string. It takes only a trivial change to the script to make this happen. Then the environment version can be the gerrit change number, possibly suffixed with a "/2" or "/3" if there are multiple review patches. This way the environment_versions will not secretly resolve and patches can reliably modify the environment_version.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/125513

[OpenStack Infra (hudson-openstack)]

Change abandoned by Doug Fish (<email address hidden>) on branch: master
Review: https://review.openstack.org/125513
Reason: better handled by https://review.openstack.org/#/c/119842/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/119842
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=0da0ea1438e81d392fd7d223e2140f87850f051d
Submitter: Jenkins
Branch: master

commit 0da0ea1438e81d392fd7d223e2140f87850f051d
Author: Akihiro Motoki <email address hidden>
Date: Tue Sep 9 02:32:15 2014 +0900

    Determine environment version based requirement files

    It is painful to increment the venv version manually because
    requirements.txt and test-requirements.txt are now updated by cron job.
    This commit changes run_tests.sh to just store two requirements
    files to .venv/environments file and check if it is up-to-date.
    (Note that the environment cache file is moved to .venv directory
    as there is no reason to store it in the top directory.)

    Closes-Bug: #1376485
    Change-Id: Ie44ccf6e2e65890baca3f316468254b600c518b1