bump baggageclaim
bump baggageclaim

[finishes #101621428]

Submodule src/github.com/concourse/baggageclaim 9570224..a4eb5ec:
  > Install file utility in docker image.
  > fix failing test

Signed-off-by: Corbin Halliwill <38cf05332854d0c00b392ad9da3fb5cec295aa83@pivotal.io>

zachgersh/concourse,CloudCredo/concourse,cjcjameson/concourse,concourse/concourse,CloudCredo/concourse,zachgersh/concourse,concourse/concourse,concourse/concourse,longnguyen11288/concourse,longnguyen11288/concourse,longnguyen11288/concourse,zachgersh/concourse,cjcjameson/concourse,cjcjameson/concourse,concourse/concourse,concourse/concourse,CloudCredo/concourse