Use uid as username when creating user with LDAP
Use uid as username when creating user with LDAP

Without that commit, each user created by a LDAP login would have the
first part of their email address as nickname.

This is not useful for LDAP, where a uid attribute is already set.

8thcolor/eurucamp2014-htdsadr,8thcolor/eurucamp2014-htdsadr,8thcolor/rubyconfau2015-sadr,8thcolor/rubyconfau2015-sadr,8thcolor/rubyconfau2015-sadr,8thcolor/eurucamp2014-htdsadr