Fix default folder configuration for Symfony 3

[rubenrubiob]

Hi!

The deployer fails when trying to deploy a Symfony 3.4 application, as the default configuration sets the folder structure as it is a Symfony 4 application. Symfony's documentation explains the architecture for 3.4 applications: https://symfony.com/doc/3.4/quick_tour/the_architecture.html

That is specially true for applications that have been upgraded from earlier versions.

I have removed the check, but maybe the checks should be more accurate? I can try to do it, if I know how versions differ between them.

Thank you!

Regards!

[YetiCGN]

See #67 for an even better approach which is configurable from userland.

[rubenrubiob]

Yes, I saw that pull request, but that would not work for Symfony 3.4 either, as the checking for versions are wrong, you can see it with the minor version checking.

But that way seems more elegant, indeed, so, if the pull request is merged, I will be happy to do a pull request changing the version checking. It is pretty simple, actually.