Bump src/loggregator

Bump :
  John Tuley:
     [#65121514] Remove unnecessary test file
  Alex Jackson:
     bump loggregator lib to pick up new emitter code
     use etcd as a distributed cache for syslog drain information
     dont set TTL for app in etcd... rely on dump sink timeout for removal
     use copy of localhost certs as encoded []byte constants rather than generating files
     refactor sink_manager to use blacklist
     move tests to httptest #test-stability
     mark flaky test as pending
     use new test logger from loggregatorlib to not use real files when testing logging
     move message router to new pattern for input chans
     better manage sinks by auto matically unregistering them with Run() returns
     import new sinkmanager package
     remove empty function
     remove unused interface
     move sinkamanger to its own package
     more deterministic tests for syslog sink #test-stability
     remove usused test file
     move websocket server to its own package
     use more un-relialable hostname in DNS failure test #test-stability
     bail on tests early when failed
     refactored sinks
     test tests with ginkgo
     fix CI
     wip
  Matthew McNew:
     Update SyslogWriter Test to use HTTPtest
     Add Ginkgo to travis path
     updated ginkgo setup
     Kick Travis Build
     fixup merge conflict badness
     Merge branch 'wip_loggregator_stages'
     green tests with refactor
     Major refactoring, stability fixes
  Jared Carroll:
     Add assertion to flaky spec
  Dakota Bailey:
     Increase KeepAlive timeout to fix tests on slow Travis box