fix concourse $PATH config

Signed-off-by: Steve Powell <spowell@pivotal.io>
loosen stop timeout for running under load

Signed-off-by: Steve Powell <spowell@pivotal.io>
quiet down concourse script

Signed-off-by: Steve Powell <spowell@pivotal.io>
end of an error

previously tests whose description lived near 997 would predictably
fail as the Garden server port clashed with the Debug server port

learn from this

Signed-off-by: Steve Powell <spowell@pivotal.io>