Comment 4 for bug 1826434

Reviewed: https://review.opendev.org/656537
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=8d8676381460d1719860f388929222eea436558d
Submitter: Zuul
Branch: stable/stein

commit 8d8676381460d1719860f388929222eea436558d
Author: Alan Bishop <email address hidden>
Date: Thu Apr 25 14:40:48 2019 -0400

    Fix swift backup driver crashing during service startup

    This patch fixes a crash in the swift backup driver during service
    startup, when the backup_swift_url is None. When backup_swift_url is
    None, the initialization code tries to fetch swift's endpoint from the
    service catalog. However, this fails during service startup because the
    context is missing the information required to access the catalog.

    Closes-Bug: #1826434
    Change-Id: I7e7dbdae72a08e663a96b6c01340ec2a5cbe883e
    (cherry picked from commit 37997388725a4469624e2e14e1575301fa7cfcf7)