bump response header timeout for baggageclaim
bump response header timeout for baggageclaim

kept GC response header timeout as 1 minute; it's best not to hold up
GC, and it's primarily volume *creates* that are prone to be slow, which
GC doesn't do.

concourse/concourse#1171

concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse