Remove deprecated fields in keystone auth middleware

This commit makes the following changes:

Use X_PROJECT_ID instead of X_TENANT_ID:
  In the latest keystone auth_token middleware it is recommended to
  use X_PROJECT_ID instead of X_TENANT_ID. X_PROJECT_ID is supported
  in auth_token middleware for both keystone v2 and v3 API.
  The corresponding change was done in keystoneclient before Grizzly
  release, so we don't need to take care of X_TENANT_ID now.

USE X_ROLES instead of X_ROLE:
  X_ROLES is now recommended.
  X_ROLE exists just for diablo backward compatibility.

Remove X_TENANT and X_USER:
  X_TENANT and X_USER are for diablo backward compatibility.
  We no longer need take care of them in Icehouse Neutron.

Change-Id: Ie714b1323ff8c44dbee66b54e683226cf675b104
Closes-Bug: #1242447
Fix import log_handler error with publish_errors set

Sync from Olso.
Commit Id is Ibf28ba17f81b5ddeda653f6a3501ecac18ffcd42

This handler sends all error logs as rpc notifications.
Note: when using publish_errors you also need to set the
notification_driver option too.

Closes-bug: #1240349
Change-Id: Ie66b23af8da2e439e0ac2f5677f6a064e3dd3133
Cleanup HACKING.rst

* Point to new location for hacking doc
(http://docs.openstack.org/developer/hacking/)
* Remove openstack-common section because already in main hacking doc

Change-Id: I7fbcfe13469a75fed08700ccbe07fefbee33db22
Replace a non-existing exception

Closes-Bug: #1242662

Change-Id: Ie44023c0fd9ba1373ec6e62d9245884b9f719b7e
Arista ML2 mech driver cleanup and integration with portbindings

fixes bug: 1215097

This patch addresses minor cleanups which are the diff between the
original version of the patch which was merged into havana master
branch and the patch that is submitted for merge into stable/havana.

The original patch that was merged into havana master branch is at:
https://review.openstack.org/#/c/49086/
The new patch which has been submitted as havana-backport-potential is:
https://review.openstack.org/#/c/54447/

This whole excercise came into play because the original patch was not
picked up in havana-rc2 because of missing tag in the bug. Therefore, the
need to submit new patch against stable/havana.

When the new patch was submitted for havana-backport-potential, few very
minor previously commented cleanups were incorporated as well. This
patch brings these minor cleanups into master branch as well. Therefore,
merge of these two patches will bring both master branch and
stable/havana at parity.

Change-Id: I4ec5273c26a27ca52b430a6c7485a44e880a1787
Merge "Arista ML2 mech driver cleanup and integration with portbindings"
Merge "Replace a non-existing exception"
Merge "Remove deprecated fields in keystone auth middleware"
Merge "Cleanup HACKING.rst"
Merge "Fix import log_handler error with publish_errors set"