Hotfix for Rspec and second storage

Rails requires a second storage for testing cross shard features. Gitaly
will not boot if this second storage doesn't exist. So this will create
this storage without adding it to the list of storages that Rails knows
about.

spec/support/helpers/test_env.rb

@@ -168,6 +168,8 @@ module TestEnv
       return
     end
 
+    FileUtils.mkdir_p("tmp/tests/second_storage") unless File.exist?("tmp/tests/second_storage")
+
     spawn_script = Rails.root.join('scripts/gitaly-test-spawn').to_s
     Bundler.with_original_env do
       raise "gitaly spawn failed" unless system(spawn_script)