Add 'log_directory' to grpc definiton
Add 'log_directory' to grpc definiton

Summary: As title

Reviewed By: fgasperij

Differential Revision: D27361185

fbshipit-source-id: fbcad3a67a58bd182229ce053c54ee83fae08327

facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl