Improve error message, by capturing the PIDs of process using 'fuser'.
2017.06.28 14:20:49.005 EDT: [ERROR] 2017-06-28 14:20:49,004:ERROR:Pegasus.db.admin.commands(82): (OperationalError) database is locked (sqlite:////home/nanohub/clarksm/.pegasus/workflow.db)