Fix naming convention of LDAP tests
Disable allow_username_or_email_login in example

The example LDAP configuration in gitlab.yml enables the
allow_username_or_email_login setting. Because the effect of this
setting is somewhat counterintuitive, I propose we make 'false' the
example default. The settings initializer already sets this setting to
'false'.
Remove LDAP::Access#find_user

This method existed to allow LDAP users to take over existing GitLab
accounts if the part before the '@' of their LDAP email attribute
matched the username of an existing GitLab user. I propose to disable
this behavior in order to prevent unintended GitLab account takeovers.

After this change it is still possible to take over an existing GitLab
account with your LDAP credentials, as long as the GitLab account email
address matches the LDAP user email address.
Add CHANGELOG entry for LDAP takeover deprecation
Rename ldap tests even further
Move and rename ldap / oauth specs
Merge branch 'ldap_allow_email' into 'master'

Avoid ldap.allow_username_or_email_login issues

See merge request !1016
Merge branch 'feature-ldap-tests' into 'master'

Feature ldap tests

Move specs to proper places. Relates to #154

This is already mergeable, will continue in a new branch for additions & refactorings.

See merge request !1053
Merge branch 'master' of github.com:gitlabhq/gitlabhq