generate_sample script can't handle MultiStrOpt when is blank list

[Xingchao Yu]

In case if opt type it multistropt and the value is [].
Then extract_opts.py can't handle this case, and will skip this option return blank content.

[Xingchao Yu (yuxcer)]

See the bug I report yeterday: https://bugs.launchpad.net/cinder/+bug/1240783

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/52573

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/52573
Committed: http://github.com/openstack/cinder/commit/e5aa6e72734738e81d1b8be51ae3bb39db50f8a3
Submitter: Jenkins
Branch: master

commit e5aa6e72734738e81d1b8be51ae3bb39db50f8a3
Author: Xingchao Yu <email address hidden>
Date: Fri Oct 18 13:50:18 2013 +0800

    Fix generate conf script can't handle multistropt

    In case MultiStrOpt option's value is empty list, current extract_opts.py
    logic will ignore it. This patch aims to update func _print_opt:

    add the multistropt's option_name in conf even its value is empty list.

    This bug also affects https://bugs.launchpad.net/cinder/+bug/1240783

    Closes-bug: #1241348

    Change-Id: Ica1da0cd20c97a587964cb0059836d609a440145