Print the log message from plugin using exec
Print the log message from plugin using exec

refs #538

SkygearIO/skygear-server,SkygearIO/skygear-server,rickmak/skygear-server,rickmak/skygear-server,rickmak/skygear-server,SkygearIO/skygear-server,SkygearIO/skygear-server