Avoid using self in service.ts - to avoid issue with `through` by willstott101 · Pull Request #95 · gabrielcsapo/node-git-server

I've been seeing errors like this during shutdown of my integration test suite.

  ● auth › repo push auth test allowed repo, specific branches

    TypeError: _this.queue is not a function

      at Stream.call (node_modules/node-git-server/dist/service.js:115:37)
      at Stream.stream.write (node_modules/through/index.js:26:11)

by switching to using the through stream via closure seems to fix the issue. Whilst in there I went ahead and tidied up the usage of self as I believe when operating inside closures of a class method... this should always refer to the same thing. By removing the self we can avoid temptation to re-define this in any closure.