Comment 7 for bug 1775518

Reviewed: https://review.openstack.org/582826
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=b8b5de985359fe07f235e8c10f375246b1608fbb
Submitter: Zuul
Branch: stable/pike

commit b8b5de985359fe07f235e8c10f375246b1608fbb
Author: Yong Huang <email address hidden>
Date: Thu Jun 7 14:39:13 2018 +0800

    Empty option value maybe cause Unity driver failed to initialize

    If the value of list type option is empty, Unity driver may failed to
    initialize.

    Example:
    unity_io_ports=
    unity_storage_pool_names=

    Change-Id: Ib5850d984bfd3651d308f448993251e9ec5a9460
    Closes-bug: #1775518
    (cherry picked from commit 2ecfd6144ba79334740407241c8fa5d7ad928840)
    (cherry picked from commit c7f9d29e17523653b7d2f0eb2b109798235b6ebb)