remove leftover SymfonyRequirements from standard-edition

this is a left-over from the standard-edition, the new way would be https://github.com/symfony/requirements-checker

Author: Tobion

.gitignore

@@ -13,7 +13,6 @@ yarn-error.log
 !/var/sessions
 /var/sessions/*
 !var/sessions/.gitkeep
-!var/SymfonyRequirements.php
 /public/build/fonts/glyphicons-*
 /public/build/images/glyphicons-*