Fix the Doctrine platform recognition

[leofeyer]

The logic of the ParametersYamlPass needs to be run before the Plugin::addDefaultServerVersion() method, otherwise the DB connection always fails and our 'server_version' => '5.5' workaround will always be applied. This breaks the Doctrine platform recognition (see #979).

[aschempp]

What if we don't add the server_version?

[Toflar]

LGTM but why is that 4.9?

[leofeyer]

What if we don't add the server_version=

Then we would have the problem described in contao/core-bundle#1422 again. 😉

LGTM but why is that 4.9?

Because the ParametersYamlPass (and support for env(DATABASE_URL)) has only been added in Contao 4.9.

[m-vo]

But the referenced issue in #979 that this PR aims to fix occurs on Contao 4.8.5?

[leofeyer]

See #979 (comment)