Recent Change to default state_path can silently break existing systems

[Phil Day]

the change to the default value of state_path introduced by
I94502bcfac8b372271acd0dbc1710c0e3009b8e1 for the reasons set out
in my -1 review of the same that seems to have been skipped when the
change was accepted.

As implemented the change will break any existing systems that are using
the default value of state_path with no warning period, which goes beyond
the scope of change for UpgradeImpact

[Matt Riedemann (mriedem)]

Adding cinder since the same change was made there: https://review.openstack.org/#/c/52372/

[Matt Riedemann (mriedem)]

Removed cinder since their version of the patch had the deprecated option name.

The nova patch is here: https://review.openstack.org/#/c/77289/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/77289
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=09dd7bf800bcfc18a2a57b9e1ce0c3c24653f5ac
Submitter: Jenkins
Branch: master

commit 09dd7bf800bcfc18a2a57b9e1ce0c3c24653f5ac
Author: Phil Day <email address hidden>
Date: Fri Feb 28 22:49:15 2014 +0000

    Reverts change to default state_path

    Reverting the change to the default value of state_path introduced by
    I94502bcfac8b372271acd0dbc1710c0e3009b8e1 for the reasons set out
    in my -1 review of the same that seems to have been skipped when the
    change was accepted.

    As implemented the change will break any existing systems that are using
    the default value of state_path with no warning period, which goes beyond
    the scope of change for UpgradeImpact

    A better approach would be to introduce a new config value that is used in
    the code, but is over-ridden by "state_path" if it is still in the config file,
    and log a warning that state_path is deprecated and will be removed in the future.

    That way the change to default behavior can be introduced at the start of the
    next release cycle by removing the deprecated state_path config value, and
    users have until then to prepare.

    It does mean that we keep the insane default for a bit longer, but I think that's
    much better that breaking a running system.

    Closes-bug: #1291515

    Change-Id: I7bb70c551ec9616276552d2e32076b66a1d3ce01