Use jpegPhoto LDAP attribute as Avatar picture
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## Implementation Plan
Based on a previous attempt at adding this feature: https://github.com/brigriffin/gitlabhq/commit/b8c5ba30919c72c5d66e9090b7b89a50cec5bb24
* Add `jpegPhoto` to `def user_attributes` in `lib/gitlab/auth/ldap/adapter.rb`
* Map `photo` to `jpegPhoto` (or `thumbnailPhoto`) in `def default_attributes` in `lib/gitlab/auth/ldap/config.rb`
* Define `photo` in `lib/gitlab/auth/ldap/person.rb` (`attribute_value(:photo)`)
* Add tests (likely to be:
* `lib/gitlab/auth/ldap/person.rb`
* `lib/gitlab/auth/ldap/config.rb`
* `lib/gitlab/auth/ldap/adapter.rb`
Bonus:
* Create a rake task to import photos/avatars for all LDAP users and add specs (probably a separate merge request)
issue