Update server.js

err应该是filter处理过的err，而不是起初的err
Revert "fix filters.toobusy"
Merge pull request #643 from wuxian/revert-641-patch-2

Revert "fix filters.toobusy"
Merge pull request #642 from wuxian/patch-1

Update server.js
Merge pull request #644 from Cosmosbox/master

Add the cancelShutDownTimer hook