Remove Composer's file and directory.

Symfony.gitignore

@@ -25,7 +25,6 @@
 /bin/*
 !bin/console
 !bin/symfony_requirements
-/vendor/
 
 # Assets and user uploads
 /web/bundles/
@@ -38,8 +37,5 @@
 # Build data
 /build/
 
-# Composer PHAR
-/composer.phar
-
 # Backup entities generated with doctrine:generate:entities command
 **/Entity/*~