PureISCSIDriver _connect needs better error handling

[Danny Wilson]

During a _connect operation the current driver will fail if a volume is already connected. We should modify this to catch the internal exception and return the correct connection information.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/142648

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/142648
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=4da33ea23319b16b8e81ee0413b0c251a444d669
Submitter: Jenkins
Branch: master

commit 4da33ea23319b16b8e81ee0413b0c251a444d669
Author: Daniel Wilson <email address hidden>
Date: Wed Dec 17 12:05:44 2014 -0800

    Add error handling to _connect function in PureISCSIDriver

    The driver was throwing an exception when trying to connect a volume
    to a host when they were already connected. This change catches the
    exception and looks up the existing connection information to use as
    a return value.

    Change-Id: Id0e6b1d3c3cd1e51745e97f99eef88a15e285526
    Closes-Bug: 1403631