Fix bootstrap build path for v3 directory structure

Author: peterjmit

lib/capistrano/tasks/symfony.rake

@@ -80,7 +80,11 @@ namespace :symfony do
   task :build_bootstrap do
     on release_roles :all do
       within release_path do
-        execute :php, build_bootstrap_path, fetch(:app_path)
+        if fetch(:symfony_directory_structure) == 2
+          execute :php, build_bootstrap_path, fetch(:app_path)
+        else
+          execute :php, build_bootstrap_path, fetch(:var_path)
+        end
       end
     end
   end