Update keystone authentication documentation

Add detailed information on how to configure gluster-swift
to use Keystone as an authentication source.

Change-Id: I9e3ea72378e3f85db45e0ab0320d43591976e038
Signed-off-by: Antonio Messina <antonio.s.messina@gmail.com>
Reviewed-on: http://review.gluster.org/6956
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>
Sync with OpenStack Swift v1.12.0

* Bumped the version of gluster-swift to v1.12.0.
* Added document on how to do a sync

Change-Id: I676e110759b0bce3007a2a38f3b384b4ca9d710d
Signed-off-by: Luis Pabon <lpabon@redhat.com>
Reviewed-on: http://review.gluster.org/6977
Reviewed-by: Prashanth Pai <ppai@redhat.com>
Reviewed-by: Chetan Risbud <crisbud@redhat.com>
Tested-by: Chetan Risbud <crisbud@redhat.com>