Use (# of CPUs) glance workers by default

[OpenStack Infra]

https://review.openstack.org/102665
commit cb7b189f4cd425cad3cbea6ca71986216416cec7
Author: Matt Riedemann <email address hidden>
Date: Wed Jun 25 14:18:36 2014 -0700

    Use (# of CPUs) glance workers by default

    The config docs have historically recommended that the number of
    glance workers should be set to the number of CPUs available for
    best performance, so we should make this the default.

    Commit 75c96a48fc7e5dfb59d8258142b01422f81b0253 did the same thing in
    Nova in Icehouse and the plan is to do the same thing for Cinder
    and Trove workers.

    The config files are updated to match the help string in the code.

    There is no upgrade impact since glance-api.conf previously
    hard-coded the workers value to 1 so anyone upgrading to this
    will still get whatever value was set in glance-api.conf prior
    to this change.

    DocImpact: glance workers will now be equal to the number of
               CPUs available by default if not explicitly specified
               in glance-api.conf and/or glance-registry.conf.

    UpgradeImpact: There is no upgrade impact to glance-api workers
               since glance-api.conf previously hard-coded the workers
               value to 1 so anyone upgrading to tihs will still get
               whatever value was set in glance-api.conf prior to
               this change. There is an upgrade impact to the
               glance-registry workers since glance-registry.conf
               did not hard-code the workers value to 1 before change
               I0cee0d284eef9ce5dcb26720499f2c4d31eaca0f, which is
               overwritten here. So anyone upgrading to this change
               that does not have workers specified in
               glance-registry.conf will now be running multiple
               workers by default when they restart the glance
               registry service.

    Closes-Bug: #1333325

    Change-Id: I6795c6e22268bb3fb67331edc7af641aefa904cc

[Tom Fifield (fifieldt)]

added to release notes