Reduce unecessary output from dispatcher when starting experiment.

Author: am009

docker/dispatcher-image/startup-dispatcher.sh

@@ -24,7 +24,7 @@ cloud_sql_proxy -instances="$CLOUD_SQL_INSTANCE_CONNECTION_NAME" &
 # Setup source code, virtualenv and dependencies.
 gsutil -m rsync -r "${EXPERIMENT_FILESTORE}/${EXPERIMENT}/input" "${WORK}"
 mkdir ${WORK}/src
-tar -xvzf ${WORK}/src.tar.gz -C ${WORK}/src
+tar -xzf ${WORK}/src.tar.gz -C ${WORK}/src
 
 # Set up credentials locally as cloud metadata service does not scale.
 credentials_file=${WORK}/creds.json