Bump src/loggregator

Bump :
  John Tuley:
     [#62673428] We are not printing out the last 20 messages anymore when tailing
     Fixing method name and typo
     Improving the error message for the end user when loggregator cannot send log messages fast enough
  Matthew McNew:
     Merge pull request #8 from cloudfoundry/remove_src_type

Signed-off-by: John Tuley <jtuley@pivotallabs.com>