Investigate flaky parallel/test-http-set-timeout-server

Version: master
Platform: freebsd,pi1-raspbian-wheezy
Subsystem: http

Example: https://ci.nodejs.org/job/node-test-commit-freebsd/7525/nodes=freebsd10-64/console

not ok 612 parallel/test-http-set-timeout-server
  ---
  duration_ms: 1.315
  severity: fail
  stack: |-
    # serverTimeout
    # serverRequestTimeout
    # serverResponseTimeout
    # serverRequestNotTimeoutAfterEnd
    # serverResponseTimeoutWithPipeline
    # idleTimeout
    ok
    
    assert.js:81
      throw new assert.AssertionError({
      ^
    AssertionError: '' === '/2'
        at process.<anonymous> (/usr/home/iojs/build/workspace/node-test-commit-freebsd/nodes/freebsd10-64/test/parallel/test-http-set-timeout-server.js:121:12)
        at emitOne (events.js:101:20)
        at process.emit (events.js:191:7)