force_config_drive: StrOpt -> BoolOpt

[OpenStack Infra]

https://review.openstack.org/237762
commit 296479e1abbfccb04584e341002401909c85be77
Author: Stephen Finucane <email address hidden>
Date: Tue Oct 20 19:41:30 2015 +0000

    force_config_drive: StrOpt -> BoolOpt

    The 'force_config_drive' option provides a way to force injection of
    configuration drives on instances. Previously, this option supported
    three values: 'always', 'True' and 'False'. However, the 'always'
    value was deprecated in Liberty and can now be removed.

    Remove this value and replace the existing 'StrOpt' with a 'BoolOpt'.
    This also requires changing some unit tests to reflect the new value
    for this parameter.

    UpgradeImpact: This change removes support for the 'always' option.
        Configuration files providing this value will need to be updated
        accordingly.
    DocImpact: This option is now a BoolOpt and documentation will need to
        be updated accordingly.
    Change-Id: I0b4030ec1336fb1f2e721570c99a27a979e2847c

[venkatamahesh (venkatamaheshkotha)]

This change is already updated. So there is no work here

https://github.com/openstack/openstack-manuals/blob/master/doc/config-reference/source/tables/nova-configdrive.rst