Disable stacktraces when using the default logger
Disable stacktraces when using the default logger

Makes the log cleaner, even though the default logger only used in tests.

cloudfoundry-incubator/bits-service,cloudfoundry-incubator/bits-service,cloudfoundry-incubator/bits-service,cloudfoundry-incubator/bits-service,cloudfoundry-incubator/bits-service