Bump src/loggregator

Bump :
  Alex Jackson:
     disable old yeti tests until new CAT test is ready
     Attempt to make tests more stable by checking the state of the channel when receiving
  Jared Carroll:
     Dont reset websocket keep alive timer when loggregator receives a message from producers
     Fix a few concurrency bugs found during airpair interview

Signed-off-by: Alex Jackson <ajackson@pivotallabs.com>