Check if sensorDataProducer is not null before checking if it's running
Check if sensorDataProducer is not null before checking if it's running

git-svn-id: 3690ca8e8b93aad95f5b520fc409c00b09b1d475@17114 6e01202a-0783-4428-890a-84243c50cc2b

concord-consortium/sensor,concord-consortium/sensor