[Security] Add an option to disable the hasPreviousSession() check in AbstractAuthenticationListener
merged branch adrienbrault/security-feature (PR #4776)

This PR was merged into the master branch.

Discussion
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[2.2] [Security] Add an option to disable the hasPreviousSession() check in AbstractAuthenticationListener

Bug fix: no
Feature addition: yes
Backwards compatibility break: no
Symfony2 tests pass: [![Build Status](https://secure.travis-ci.org/adrienbrault/symfony.png?branch=security-feature)](http://travis-ci.org/adrienbrault/symfony)
Fixes the following tickets: #3703
Todo: Add this option to the symfony doc security configuration reference
License of the code: MIT
Documentation PR: N/A

As stated in #3703, all authentication listeners that inherit from AbstractAuthenticationListener, only work when a previous session has been created.
This PR allows to change the default behavior in the security.yml file.

Example:

```yml
security:
    firewalls:
        secured_area:
            pattern:    ^/demo/secured/
            form_login:
                check_path: /demo/secured/login_check
                login_path: /demo/secured/login
                require_previous_session: false # The default value is true
            logout:
                path:   /demo/secured/logout
                target: /demo/
            #anonymous: ~
            #http_basic:
            #    realm: "Secured Demo Area"
```

PS: While removing my old commit, it closed the #4774 PR ...

Commits
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0562463 [Security] Add an option to disable the hasPreviousSession() check in AbstractAuthenticationListener