Email shouldn't be a mandatory attribute

[Julie Pichon]

When using a LDAP backend, it's possible that a user won't have the "email" attribute defined, however it should still be possible to edit the other fields.

Steps to reproduce (in an environment with keystone using a LDAP backend):
1. Log in as admin
2. Go to the Users dashboard
3. Select a user that doesn't have an email defined

Expected result:
4. "Edit user" modal opens

Actual result:
4. Error 500

Traceback:
File "/usr/lib/python2.7/site-packages/django/views/generic/edit.py" in get
  154. form = self.get_form(form_class)
File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/forms/views.py" in get_form
  82. return form_class(self.request, **self.get_form_kwargs())
File "/usr/lib/python2.7/site-packages/django/views/generic/edit.py" in get_form_kwargs
  41. kwargs = {'initial': self.get_initial()}
File "/opt/stack/horizon/openstack_dashboard/wsgi/../../openstack_dashboard/dashboards/admin/users/views.py" in get_initial
  103. 'email': user.email}
File "/opt/stack/python-keystoneclient/keystoneclient/base.py" in __getattr__
  425. raise AttributeError(k)

Exception Type: AttributeError at /admin/users/e005aa43475b403c8babdff86ea27c37/update/
Exception Value: email

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/61837

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/61837
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=faf5b2aead067ab00a936249085f65886edcb483
Submitter: Jenkins
Branch: master

commit faf5b2aead067ab00a936249085f65886edcb483
Author: Julie Pichon <email address hidden>
Date: Thu Dec 12 17:42:20 2013 +0000

    Gracefully handle Users with no email attribute

    In certain environments, such as when using Keystone with a LDAP
    backend, it's possible that the email attribute won't exist for all
    users.

    Change-Id: I71041be832206e52bfb73926199f2c89e0e84a0b
    Closes-Bug: #1260423

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/havana
Review: https://review.openstack.org/62613

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/62613
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=82b6e108d2a5233be3cc4bd254599f6c878f2dda
Submitter: Jenkins
Branch: stable/havana

commit 82b6e108d2a5233be3cc4bd254599f6c878f2dda
Author: Julie Pichon <email address hidden>
Date: Thu Dec 12 17:42:20 2013 +0000

    Gracefully handle Users with no email attribute

    In certain environments, such as when using Keystone with a LDAP
    backend, it's possible that the email attribute won't exist for all
    users.

    Change-Id: I71041be832206e52bfb73926199f2c89e0e84a0b
    Closes-Bug: #1260423

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/62839

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/62839
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=19566878b24925bf423fe9588652ea59322af58d
Submitter: Jenkins
Branch: master

commit 19566878b24925bf423fe9588652ea59322af58d
Author: Dirk Mueller <email address hidden>
Date: Wed Dec 18 11:28:37 2013 +0100

    User email is optional and can be absent

    Change-Id: Idff0f7c33bcaee29c7d1e7be415eb6b5b29b5b1a
    Related-Bug: #1260423

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: stable/grizzly
Review: https://review.openstack.org/69552

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/69552
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=3212dd03738e90a7b3bbc7ecb46317a0a8cc9c02
Submitter: Jenkins
Branch: stable/grizzly

commit 3212dd03738e90a7b3bbc7ecb46317a0a8cc9c02
Author: Dirk Mueller <email address hidden>
Date: Wed Dec 18 11:28:37 2013 +0100

    User email is optional and can be absent

    cherry-picked from faf5b2aead067ab00a936249085f65886edcb483
    cherry-picked from 19566878b24925bf423fe9588652ea59322af58d

    Change-Id: Idff0f7c33bcaee29c7d1e7be415eb6b5b29b5b1a
    Related-Bug: #1260423