Cinder ISCSI Driver has no 'target_helper' member

[Nickita Zaporozhets]

This bug has already been fixed in master (https://bugs.launchpad.net/cinder/+bug/1400804), fix was backported to Juno, but MOS 6.1 is still affected.

[Fuel Devops McRobotson (fuel-devops-robot)]

Fix proposed to branch: openstack-ci/fuel-6.1/2014.2
Change author: John Griffith <email address hidden>
Review: https://review.fuel-infra.org/10623

[Vitaly Sedelnik (vsedelnik)]

Invalid for 7.0 as the fix is in Kilo

[Vitaly Sedelnik (vsedelnik)]

Probably we should merge it for 6.1 because the fix came from the upstream (we have not env with Solidfire to validate it)

[Fuel Devops McRobotson (fuel-devops-robot)]

Reviewed: https://review.fuel-infra.org/10623
Submitter: Vitaly Sedelnik <email address hidden>
Branch: openstack-ci/fuel-6.1/2014.2

Commit: a5b4b80d08845c33f06d1743c0dbd68efcf033b3
Author: John Griffith <email address hidden>
Date: Thu Aug 20 17:07:58 2015

Remove iscsi_helper calls from base iscsi driver

There are a number of drivers that inherit from the base
iscsi driver, using the base implementation of initialize_connection
and terminate_connection. These drivers also don't have iscsi_helper
defined.

We've kept all iscsi_helper specific code in the tgt helpers
themselves, or in the various versions of the LVM driver
which is where they belong.

Over time however there have been some iscsi_helper specific
calls that have crept in to the base volume.driver:ISCSIDriver
class. These were LIO specific calls and as a result when a
configuration is set with multi-backend to use lioadm as the
target helper, or even if it's not used but the default iscsi_helper
is set to lioadm the initialize_connection and terminate_connection
calls will try and access the LIO specific calls and raise because
the drivers inheriting from this class don't have target_helper
members.

This went unnoticed mostly because there's no significant LIO testing
in place and there were no distros setting LIO as the default iscsi_helper,
it appears that this has changed however.

This patch moves the LIO specific calls back where they belong
and keeps the base ISCSIDriver generic. I've also added a test
case for this in the SolidFire driver because it's impacted by
this.

Closes-Bug: #1481523
(cherry picked from commit 7095e1c5a7477ca77c8698d96a969a7d78090a18)

Change-Id: Ia40215eb89d83bd1a86411760b51a40fa4b0cd14