create_export and remove_export broken in driver.py

[Avishay Traeger]

There are some issues with create_export and remove_export in driver.py:
1) There is a call to a create_export RPC, but the volume manager does not implement create_export
2) remove_export is not called in _detach_volume in driver.py, which means we have exports left over from several calls

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/76471

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/76471
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=b868ae707f9ecbe254101e21d9d7ffa0b05b17d1
Submitter: Jenkins
Branch: master

commit b868ae707f9ecbe254101e21d9d7ffa0b05b17d1
Author: Avishay Traeger <email address hidden>
Date: Wed Feb 26 11:27:06 2014 +0200

    Fix create_export/remove_export in driver.py

    1. There was a call to rpcapi.create_export which does not have a
    matching volume manager function, causing volume migration to crash.
    This call was not necessary because there is already an
    initialize_connection RPC call, which calls the driver's create_export
    function. Removed the create_export RPC call and function. Added better
    error handling to that code in _attach_volume in driver.py as well.

    2. The manager called remove_export from detach_volume, which was not
    being called by these functions. I believe it makes more sense to call
    it from terminate_connection. Moved it there, and fixed up the
    corresponding code in _detach_volume in driver.py.

    3. Remove leftovers of export code from create_volume manager flow.

    Change-Id: I2b192630ebed54368f151db47b49cbc72601a8d7
    Closes-Bug: #1285060