poll a little less frequently in acceptance suite
poll a little less frequently in acceptance suite

default is 10ms which is a bit low

Signed-off-by: Toby Rumans <516e7840355d33b790e9dc5c111fe7c7c270a08f@pivotal.io>

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