Improper check for implemented driver methods

[Lucian Petrut]

The base ShareDriver "_has_redefined_driver_methods" method checks if a stub method was implemented by comparing it to the super class method.

This can cause issues if those methods are inherited, being actually implemented in the super class, which does not have to be
the base ShareDriver class (for example, we could have common classes, inherited by multiple drivers).

At the moment, this method is used when checking if a driver supports snapshots.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/220511
Committed: https://git.openstack.org/cgit/openstack/manila/commit/?id=c6c2894821034a4ad87bf2e5e1d2676b84d2d760
Submitter: Jenkins
Branch: master

commit c6c2894821034a4ad87bf2e5e1d2676b84d2d760
Author: Lucian Petrut <email address hidden>
Date: Fri Sep 4 16:33:03 2015 +0300

    Enhance base driver checking if a method was implemented

    The base ShareDriver "_has_redefined_driver_methods" method
    checks if a stub method was implemented by comparing it to the
    super class method.

    This can cause issues if those methods are inherited, being
    actually implemented in the super class, which does not have to be
    the base ShareDriver class (for example, we could have common
    classes, inherited by multiple drivers).

    This patch fixes this by comparing the methods being tested with
    the ones from the ShareDriver class.

    Also, the create_share_from_snapshot method was removed from the
    Huawei driver as it was actually just raising NotImplementedError.
    This was misleading for our way of checking if a driver supports
    snapshotting.

    Closes-Bug: #1492311

    Change-Id: I0369d086234053e5495a35db5034f7344c6c323a