[Components][Security] Taking the Security component split into account

[xabbuh]

Starting with Symfony 2.4, the Security component has been split into four packages: symfony/security-acl, symfony/security-core, symfony/security-csrf and symfony/security-http. This should be documented in some way at least in the components documentation.

[javiereguiluz]

This issue was supossedly fixed by #5435. I don't know if you still consider it unfixed or if there was some error with the tool that closes issues when merging pull requests. Thanks.

[wouterj]

As the PR was merged with a squash, the commit was not a proper merge commit. This means that GitHub will only close the issues after "closes" in the commit message once the commit was merged into the master branch.