EMC VMAX does not handle delete case where volume no longer exists on backend

[Carl Pecinovsky]

Scenario:

1. Create new volume (backend deviceID = 0944)
2. On Solutions Enabler (or UniSphere) unbind 0944 from the pool and de-allocate.
3. From OpenStack, delete volume.
Volume goes into "Error Deleting" state and cannot be removed from management without manual steps.

In emc_vmax_common.py --> _delete_volume(), one of the first things it does is:

        volumeInstance = self._find_lun(volume)
        if volumeInstance is None:
            LOG.error(_("Volume %(name)s not found on the array. "
                        "No volume to delete.")
                      % {'name': volumeName})
            return errorRet

However, _find_lun() does a GetInstance(cim_path) and this will raise an exception if the volume no longer exists rather than returning None as the code expects.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/140586

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/140586
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=c634b095b7cc0750d0e5d9eb75d800773f5c929f
Submitter: Jenkins
Branch: master

commit c634b095b7cc0750d0e5d9eb75d800773f5c929f
Author: Xing Yang <email address hidden>
Date: Fri Dec 19 12:45:45 2014 -0500

    Handle the volume not found case in the VMAX driver

    When a volume cannot be found on the array, VMAX driver throws
    an exception. This brings a volume into error_deleting state during
    the volume deletion operation. This patch fixed it by returning None
    when a volume cannot be found.

    Closes-Bug: #1395830
    Change-Id: Iad714ff6e577bc9d7cf69b8654a7eb726969279e